# SFTPServer Class

The SFTPServer class is used to create a Secure File Transfer Protocol (SFTP) server.

## Syntax

```text
ipworksedi.SFTPServer
```

## Remarks

The SFTPServer class provides a simple way to create a Secure File Transfer Protocol (SFTP) server. Any SFTP client will be able to connect and transfer files to and from the server.

### Getting Started

To begin, first provide a valid certificate with a private key in the [SSHCert](#sshcert-property-sftpserver-class) property.

Optionally set the [RootDirectory](#rootdirectory-property-sftpserver-class) property to a valid local path. If this property is set, the class will serve files from this location, and when clients connect, they will see this as their initial directory. If this property is not set, then the class will fire events allowing customized responses for each operation.

To start the server, set [Listening](#listening-property-sftpserver-class) to True.

### Client Authentication

Client authentication is handled through the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event. Inside this event, the *Accept* parameter determines whether authentication is accepted; this parameter should be set to *True* if a successful authentication is detected and *False* otherwise.

When a client connects, the *AuthMethod* parameter indicates the method of authentication the client wishes to use. Connecting clients will initially attempt authentication with an *AuthMethod* of "none". This is done with the expectation that the request will fail and the server will provide a list of support authentication methods. The client then selects an available method and reauthenticates. If *AuthMethod* is "none", *Accept* should be set to *False*.

 For **password** authentication, the *User* parameter will hold the client's username and the *AuthParam* parameter will hold the password provided by the client. An external list of known usernames and passwords should be maintained to check these values against.

For **publickey** authentication, the *User* parameter will hold the client's username and the *AuthParam* parameter will hold the key provided by the client. This key should be compared to an external list of known keys and usernames.

For **keyboard-interactive** authentication, the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event will fire multiple times; once for each prompt and response sent by the client. The index of the response is specified as a suffix in the *AuthMethod* parameter (e.g., keyboard-interactive-1, keyboard-interactive-2), and *AuthParam* will contain the client's response to the prompt. Finally, [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) will fire one last time with *AuthMethod* set to "keyboard-interactive" and *AuthParam* set to an empty string. The *Accept* parameter must be set to *True* each time the event fires for the authentication process to succeed.

### Directory Listing

When a client requests a directory listing, the [DirList](#dirlist-event-sftpserver-class) event fires with the *Path* parameter set to the directory to enumerate. If the directory listing is allowed, the appropriate set of files should be passed to the [SetFileList](#setfilelist-method-sftpserver-class) method. The *StatusCode* parameter should be set according to the status of the operation, and the valid status codes can be found in the documentation for the [DirList](#dirlist-event-sftpserver-class) event.

### Handling Events

Event handlers are the primary method of customizing the class's functionality. When a client attempts to connect, open a file, authenticate to the server, and so on, the corresponding SFTPServer event will fire to allow for custom handling of the client's request.

The following events are fired **both before and after** the requested operation is executed:

- [DirCreate](#dircreate-event-sftpserver-class)
- [DirList](#dirlist-event-sftpserver-class)
- [DirRemove](#dirremove-event-sftpserver-class)
- [FileOpen](#fileopen-event-sftpserver-class)
- [FileRemove](#fileremove-event-sftpserver-class)
- [FileRename](#filerename-event-sftpserver-class)
- [FileWrite](#filewrite-event-sftpserver-class)
- [SetAttributes](#setattributes-event-sftpserver-class)

Each of these events has a *BeforeExec* event parameter that is *True* when the event is fired before execution of the operation, and *False* after execution of the operation. Handling the event before execution provides an opportunity to use custom logic to determine whether the operation should be denied, diverted, or otherwise modified. Handling the event after execution provides an opportunity to report success or any errors related to the operation to the client.

The following events are fired only **after** the requested operation is executed:

- [FileClose](#fileclose-event-sftpserver-class)
- [FileRead](#fileread-event-sftpserver-class)
- [GetAttributes](#getattributes-event-sftpserver-class)
- [ResolvePath](#resolvepath-event-sftpserver-class)

Any logic to deny opening a file for read or write should be done in the [FileOpen](#fileopen-event-sftpserver-class) event handler.

NOTE: Server components are designed to process events as they occur. To ensure that events are processed in a timely manner, [DoEvents](#doevents-method-sftpserver-class) should be called in a loop after the server is started.

## Property List

*The following is the full list of the properties of the class with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [ConnectionBacklog](#connectionbacklog-property-sftpserver-class) | This property includes the maximum number of pending connections maintained by the Transmission Control Protocol (TCP)/IP subsystem. |
| [Connections](#connections-property-sftpserver-class) | The collection of currently connected secure file transfer protocol (SFTP) clients. |
| [DefaultAuthMethods](#defaultauthmethods-property-sftpserver-class) | The supported authentication methods. |
| [DefaultTimeout](#defaulttimeout-property-sftpserver-class) | The initial timeout value to be used by incoming connections. |
| [KeyboardInteractiveMessage](#keyboardinteractivemessage-property-sftpserver-class) | The instructions to send to the client during keyboard-interactive authentication. |
| [KeyboardInteractivePrompts](#keyboardinteractiveprompts-property-sftpserver-class) | A collection of prompts to present to the user during keyboard-interactive authentication. |
| [Listening](#listening-property-sftpserver-class) | This property indicates whether the class is listening for incoming connections on LocalPort. |
| [LocalHost](#localhost-property-sftpserver-class) | The name of the local host or user-assigned IP interface through which connections are initiated or accepted. |
| [LocalPort](#localport-property-sftpserver-class) | The Transmission Control Protocol (TCP) port in the local host where the class listens. |
| [RootDirectory](#rootdirectory-property-sftpserver-class) | The root directory for the entire secure file transfer protocol (SFTP) server. |
| [SSHCert](#sshcert-property-sftpserver-class) | The certificate(s) to be used during Secure Shell (SSH) negotiation. |
| [SSHCompressionAlgorithms](#sshcompressionalgorithms-property-sftpserver-class) | The comma-separated list containing all allowable compression algorithms. |
| [SSHEncryptionAlgorithms](#sshencryptionalgorithms-property-sftpserver-class) | The comma-separated list containing all allowable encryption algorithms. |

## Method List

*The following is the full list of the methods of the class with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Config](#config-method-sftpserver-class) | Sets or retrieves a configuration setting. |
| [Disconnect](#disconnect-method-sftpserver-class) | This method disconnects the specified client. |
| [DoEvents](#doevents-method-sftpserver-class) | This method processes events from the internal message queue. |
| [ExchangeKeys](#exchangekeys-method-sftpserver-class) | Causes the class to exchange a new set of session keys on the specified connection. |
| [Reset](#reset-method-sftpserver-class) | This method will reset the class. |
| [SetFileList](#setfilelist-method-sftpserver-class) | Sets the file list for a connection during a directory listing request. |
| [Shutdown](#shutdown-method-sftpserver-class) | This method shuts down the server. |
| [StartListening](#startlistening-method-sftpserver-class) | This method starts listening for incoming connections. |
| [StopListening](#stoplistening-method-sftpserver-class) | This method stops listening for new connections. |

## Event List

*The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Connected](#connected-event-sftpserver-class) | Fired immediately after a connection completes (or fails). |
| [ConnectionRequest](#connectionrequest-event-sftpserver-class) | This event is fired when a request for connection comes from a remote host. |
| [DirCreate](#dircreate-event-sftpserver-class) | Fired when a client wants to create a new directory. |
| [DirList](#dirlist-event-sftpserver-class) | Fired when a client attempts to open a directory for listing. |
| [DirRemove](#dirremove-event-sftpserver-class) | Fired when a client wants to delete a directory. |
| [Disconnected](#disconnected-event-sftpserver-class) | This event is fired when a connection is closed. |
| [Error](#error-event-sftpserver-class) | Fired when errors occur during data delivery. |
| [FileClose](#fileclose-event-sftpserver-class) | Fired when a client attempts to close an open file or directory handle. |
| [FileOpen](#fileopen-event-sftpserver-class) | Fired when a client wants to open or create a file. |
| [FileRead](#fileread-event-sftpserver-class) | Fired when a client wants to read from an open file. |
| [FileRemove](#fileremove-event-sftpserver-class) | Fired when a client wants to delete a file. |
| [FileRename](#filerename-event-sftpserver-class) | Fired when a client wants to rename a file. |
| [FileWrite](#filewrite-event-sftpserver-class) | Fired when a client wants to write to an open file. |
| [GetAttributes](#getattributes-event-sftpserver-class) | Fired when a client needs to get file information. |
| [Log](#log-event-sftpserver-class) | Fired once for each log message. |
| [ResolvePath](#resolvepath-event-sftpserver-class) | Fired when a client attempts to canonicalize a path. |
| [SetAttributes](#setattributes-event-sftpserver-class) | Fired when a client attempts to set file or directory attributes. |
| [SSHStatus](#sshstatus-event-sftpserver-class) | Fired to track the progress of the secure connection. |
| [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) | Fired when a client attempts to authenticate a connection. |

## Config Settings

*The following is a list of config settings for the class with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [DirListBufferSize\[ConnectionId\]](#DirListBufferSize[ConnectionId]) | The number of entries to be returned in one response to a request for a directory listing. |
| [MaskSensitiveData](#MaskSensitiveData) | Masks passwords in logs. |
| [MaxStartupsConnections](#MaxStartupsConnections) | The number of unauthenticated connections that the server will accept. |
| [ProtocolVersion](#ProtocolVersion) | The highest allowable SFTP version to use. |
| [RestrictUserToHomeDir\[ConnectionId\]](#RestrictUserToHomeDir[ConnectionId]) | Whether to restrict the user to their home directory. |
| [ServerEOL](#ServerEOL) | Specifies the line endings used in files on the server. |
| [SFTPErrorMessage\[ConnectionId\]](#SFTPErrorMessage[ConnectionId]) | Specifies the error message to be returned to the client. |
| [UnixStyleDateFormat](#UnixStyleDateFormat) | Controls whether to use the Unix-style date format in directory listings. |
| [UserRootDirectory\[ConnectionId\]](#UserRootDirectory[ConnectionId]) | The path of the server root directory for a particular user. |
| [AltSSHCertCount](#AltSSHCertCount) | The number of records in the AltSSHCert configuration settings. |
| [AltSSHCertStore\[i\]](#AltSSHCertStore[i]) | The name of the certificate store. |
| [AltSSHCertStorePassword\[i\]](#AltSSHCertStorePassword[i]) | The password used to open the certificate store. |
| [AltSSHCertStoreType\[i\]](#AltSSHCertStoreType[i]) | The type of certificate store. |
| [AltSSHCertSubject\[i\]](#AltSSHCertSubject[i]) | The alternative certificate subject. |
| [ClientSSHVersionString\[ConnectionId\]](#ClientSSHVersionString[ConnectionId]) | The client's version string. |
| [FireAuthRequestAfterSig](#FireAuthRequestAfterSig) | Whether to fire an informational event after the public key signature has been verified. |
| [KeyboardInteractivePrompts\[ConnectionId\]](#KeyboardInteractivePrompts[ConnectionId]) | Specifies custom keyboard-interactive prompts for particular connections. |
| [KeyRenegotiationThreshold](#KeyRenegotiationThreshold) | Sets the threshold for the SSH Key Renegotiation. |
| [LogLevel](#LogLevel) | Specifies the level of detail that is logged. |
| [MaxAuthAttempts](#MaxAuthAttempts) | The maximum authentication attempts allowed before forcing a disconnect. |
| [NegotiatedStrictKex\[ConnectionId\]](#NegotiatedStrictKex[ConnectionId]) | Returns whether strict key exchange was negotiated to be used. |
| [ServerSSHVersionString](#ServerSSHVersionString) | The SSH version string sent to connecting clients. |
| [SSHKeepAliveCountMax](#SSHKeepAliveCountMax) | The maximum number of keep alive packets to send without a response. |
| [SSHKeepAliveInterval](#SSHKeepAliveInterval) | The interval between keep alive packets. |
| [SSHKeyExchangeAlgorithms](#SSHKeyExchangeAlgorithms) | Specifies the supported key exchange algorithms. |
| [SSHMacAlgorithms](#SSHMacAlgorithms) | Specifies the supported Mac algorithms. |
| [SSHPubKeyAuthSigAlgorithms](#SSHPubKeyAuthSigAlgorithms) | Specifies the allowed signature algorithms used by a client performing public key authentication. |
| [SSHPublicKeyAlgorithms](#SSHPublicKeyAlgorithms) | Specifies the supported public key algorithms for the server's public key. |
| [SSHVersionPattern](#SSHVersionPattern) | The pattern used to match the remote host's version string. |
| [UserAuthBanner\[ConnectionId\]](#UserAuthBanner[ConnectionId]) | A custom user authentication banner. |
| [UseStrictKeyExchange](#UseStrictKeyExchange) | Specifies how strict key exchange is supported. |
| [AllowedClients](#AllowedClients) | A comma-separated list of host names or IP addresses that can access the class. |
| [BindExclusively](#BindExclusively) | Whether or not the class considers a local port reserved for exclusive use. |
| [BlockedClients](#BlockedClients) | A comma-separated list of host names or IP addresses that cannot access the class. |
| [CloseStreamAfterTransfer](#CloseStreamAfterTransfer) | If true, the class will close the upload or download stream after the transfer. |
| [DefaultConnectionTimeout](#DefaultConnectionTimeout) | The inactivity timeout applied to the SSL handshake. |
| [InBufferSize](#InBufferSize) | The size in bytes of the incoming queue of the socket. |
| [KeepAliveInterval](#KeepAliveInterval) | The retry interval, in milliseconds, to be used when a TCP keep-alive packet is sent and no response is received. |
| [KeepAliveTime](#KeepAliveTime) | The inactivity time in milliseconds before a TCP keep-alive packet is sent. |
| [MaxConnections](#MaxConnections) | The maximum number of connections available. |
| [OutBufferSize](#OutBufferSize) | The size in bytes of the outgoing queue of the socket. |
| [PreferredDHGroupBits](#PreferredDHGroupBits) | Size of the Diffie-Hellman group, in bits. |
| [TcpNoDelay](#TcpNoDelay) | Whether or not to delay when sending packets. |
| [UseIPv6](#UseIPv6) | Whether to use IPv6. |
| [LogSSLPackets](#LogSSLPackets) | Controls whether SSL packets are logged when using the internal security API. |
| [ReuseSSLSession](#ReuseSSLSession) | Determines if the SSL session is reused. |
| [SSLCACerts](#SSLCACerts) | A newline separated list of CA certificates to be included when performing an SSL handshake. |
| [SSLCheckCRL](#SSLCheckCRL) | Whether to check the Certificate Revocation List for the server certificate. |
| [SSLCheckOCSP](#SSLCheckOCSP) | Whether to use OCSP to check the status of the server certificate. |
| [SSLCipherStrength](#SSLCipherStrength) | The minimum cipher strength used for bulk encryption. |
| [SSLClientCACerts](#SSLClientCACerts) | A newline separated list of CA certificates to use during SSL client certificate validation. |
| [SSLContextProtocol](#SSLContextProtocol) | The protocol used when getting an SSLContext instance. |
| [SSLEnabledCipherSuites](#SSLEnabledCipherSuites) | The cipher suite to be used in an SSL negotiation. |
| [SSLEnabledProtocols](#SSLEnabledProtocols) | Used to enable/disable the supported security protocols. |
| [SSLEnableRenegotiation](#SSLEnableRenegotiation) | Whether the renegotiation_info SSL extension is supported. |
| [SSLIncludeCertChain](#SSLIncludeCertChain) | Whether the entire certificate chain is included in the SSLServerAuthentication event. |
| [SSLKeyLogFile](#SSLKeyLogFile) | The location of a file where per-session secrets are written for debugging purposes. |
| [SSLNegotiatedCipher](#SSLNegotiatedCipher) | Returns the negotiated cipher suite. |
| [SSLNegotiatedCipherStrength](#SSLNegotiatedCipherStrength) | Returns the negotiated cipher suite strength. |
| [SSLNegotiatedCipherSuite](#SSLNegotiatedCipherSuite) | Returns the negotiated cipher suite. |
| [SSLNegotiatedKeyExchange](#SSLNegotiatedKeyExchange) | Returns the negotiated key exchange algorithm. |
| [SSLNegotiatedKeyExchangeStrength](#SSLNegotiatedKeyExchangeStrength) | Returns the negotiated key exchange algorithm strength. |
| [SSLNegotiatedVersion](#SSLNegotiatedVersion) | Returns the negotiated protocol version. |
| [SSLServerCACerts](#SSLServerCACerts) | A newline separated list of CA certificates to use during SSL server certificate validation. |
| [SSLTrustManagerFactoryAlgorithm](#SSLTrustManagerFactoryAlgorithm) | The algorithm to be used to create a TrustManager through TrustManagerFactory. |
| [TLS12SignatureAlgorithms](#TLS12SignatureAlgorithms) | Defines the allowed TLS 1.2 signature algorithms when SSLProvider is set to Internal. |
| [TLS12SupportedGroups](#TLS12SupportedGroups) | The supported groups for ECC. |
| [TLS13KeyShareGroups](#TLS13KeyShareGroups) | The groups for which to pregenerate key shares. |
| [TLS13SignatureAlgorithms](#TLS13SignatureAlgorithms) | The allowed certificate signature algorithms. |
| [TLS13SupportedGroups](#TLS13SupportedGroups) | The supported groups for (EC)DHE key exchange. |
| [BuildInfo](#BuildInfo) | Information about the product's build. |
| [GUIAvailable](#GUIAvailable) | Whether or not a message loop is available for processing events. |
| [LicenseInfo](#LicenseInfo) | Information about the current license. |
| [MaskSensitiveData](#MaskSensitiveData) | Whether sensitive data is masked in log messages. |
| [UseDaemonThreads](#UseDaemonThreads) | Whether threads created by the class are daemon threads. |
| [UseFIPSCompliantAPI](#UseFIPSCompliantAPI) | Tells the class whether or not to use FIPS certified APIs. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |
| [UseVirtualThreads](#UseVirtualThreads) | Whether threads created by the class use virtual threads instead of platform threads. |

# ConnectionBacklog Property ([SFTPServer](#sftpserver-class) Class)

This property includes the maximum number of pending connections maintained by the Transmission Control Protocol (TCP)/IP subsystem.

## Syntax

```text
public int getConnectionBacklog();
public void setConnectionBacklog(int connectionBacklog);
```

## Default Value

5

## Remarks

This property contains the maximum number of pending connections maintained by the TCP/IP subsystem. This value reflects the SOMAXCONN option for the main listening socket. The default value for most systems is 5. You may set this property to a larger value if the server is expected to receive a large number of connections, and queuing them is desirable.

This property is not available at design time.

# Connections Property ([SFTPServer](#sftpserver-class) Class)

The collection of currently connected secure file transfer protocol (SFTP) clients.

## Syntax

```text
public SFTPConnectionMap getConnections();
```

## Remarks

This property is the collection of currently connected clients. All of the connections may be managed using this property. Each connection is described by the different fields of the [SFTPConnection](#sftpconnection-type) type.

This property is read-only.

 Please refer to the [SFTPConnection](#sftpconnection-type) type for a complete list of fields.

# DefaultAuthMethods Property ([SFTPServer](#sftpserver-class) Class)

The supported authentication methods.

## Syntax

```text
public String getDefaultAuthMethods();
public void setDefaultAuthMethods(String defaultAuthMethods);
```

## Default Value

"password,publickey"

## Remarks

This property specifies the supported authentication methods. The client will choose one of the supported mechanisms when authenticating to the class.

This must be a comma-separated list of values. For more information on authenticating clients, see the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event.

The following is a list of methods implemented by the class:

|  |  |
| --- | --- |
| none | This authentication method is used by most Secure Shell (SSH) clients to obtain the list of authentication methods available for the user's account. In most cases, you should not accept a request using this authentication method. |
| password | AuthParam will contain the user-supplied password. If the password is correct, set Accept to True. |
| publickey | AuthParam will contain an SSH2 public key blob. If the user's public key is acceptable, set Accept or PartialSuccess to true. The class will then handle verifying the digital signature and will respond to the client accordingly. |
| keyboard-interactive | [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) will fire multiple times for keyboard-interactive authentication: It will fire once for each response sent by the client in the SSH_MSG_USERAUTH_INFO_RESPONSE packet (one time for each prompt specified by the daemon). The index of each response will be specified as a suffix in AuthMethod, with AuthParam containing the response to the corresponding prompt (e.g., keyboard-interactive-1, keyboard-interactive-2, and so on). Finally, [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) will fire one last time with AuthMethod set to "keyboard-interactive" and AuthParam set to an empty string. The daemon must set Accept to True every time to allow the authentication process to succeed. |

# DefaultTimeout Property ([SFTPServer](#sftpserver-class) Class)

The initial timeout value to be used by incoming connections.

## Syntax

```text
public int getDefaultTimeout();
public void setDefaultTimeout(int defaultTimeout);
```

## Default Value

60

## Remarks

If the DefaultTimeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If DefaultTimeout is set to a positive value, the class will wait for the operation to complete before returning control.

The class will use [DoEvents](#doevents-method-sftpserver-class) to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not freeze and remains responsive.

If Timeout expires, and the operation is not yet complete, the class throws an exception.

NOTE: By default, all timeouts are *inactivity timeouts*, that is, the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the DefaultTimeout property is 60 (seconds).

# KeyboardInteractiveMessage Property ([SFTPServer](#sftpserver-class) Class)

The instructions to send to the client during keyboard-interactive authentication.

## Syntax

```text
public String getKeyboardInteractiveMessage();
public void setKeyboardInteractiveMessage(String keyboardInteractiveMessage);
```

## Default Value

""

## Remarks

This property should be set to the main instructions to send to the client during keyboard-interactive authentication.

# KeyboardInteractivePrompts Property ([SFTPServer](#sftpserver-class) Class)

A collection of prompts to present to the user during keyboard-interactive authentication.

## Syntax

```text
public SSHPromptList getKeyboardInteractivePrompts();
```

## Remarks

This property is a collection of prompts to present to the user during keyboard-authentication. It is used together with the [KeyboardInteractiveMessage](#keyboardinteractivemessage-property-sftpserver-class) property.

 Please refer to the [SSHPrompt](#sshprompt-type) type for a complete list of fields.

# Listening Property ([SFTPServer](#sftpserver-class) Class)

This property indicates whether the class is listening for incoming connections on LocalPort.

## Syntax

```text
public boolean isListening();
```

## Default Value

False

## Remarks

This property indicates whether the class is listening for connections on the port specified by the [LocalPort](#localport-property-sftpserver-class) property. Use the [StartListening](#startlistening-method-sftpserver-class) and [StopListening](#stoplistening-method-sftpserver-class) methods to control whether the class is listening.

This property is read-only and not available at design time.

# LocalHost Property ([SFTPServer](#sftpserver-class) Class)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

## Syntax

```text
public String getLocalHost();
public void setLocalHost(String localHost);
```

## Default Value

""

## Remarks

This property contains the name of the local host as obtained by the *gethostname()* system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the class initiate connections (or accept in the case of server classes) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.

If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

# LocalPort Property ([SFTPServer](#sftpserver-class) Class)

The Transmission Control Protocol (TCP) port in the local host where the class listens.

## Syntax

```text
public int getLocalPort();
public void setLocalPort(int localPort);
```

## Default Value

22

## Remarks

The LocalPort property must be set before TCPServer starts listening. If its value is 0, then the TCP/IP subsystem picks a port number at random. The port number can be found by checking the value of the LocalPort property after TCPServer is in listening mode (after successfully assigning True to the [Listening](#listening-property-sftpserver-class) property).

NOTE: The service port is not shared among servers (i.e., only one TCPServer can be 'listening' on a particular port at one time).

# RootDirectory Property ([SFTPServer](#sftpserver-class) Class)

The root directory for the entire secure file transfer protocol (SFTP) server.

## Syntax

```text
public String getRootDirectory();
public void setRootDirectory(String rootDirectory);
```

## Default Value

""

## Remarks

RootDirectory specifies the root of the SFTP server ('/'). If a value is provided, the class will handle all requests by doing all file operations itself, but the events will still give you the opportunity to override the default values and operations, as necessary.

If a value is not provided, all events must be handled appropriately to ensure correct operation.

# SSHCert Property ([SFTPServer](#sftpserver-class) Class)

The certificate(s) to be used during Secure Shell (SSH) negotiation.

## Syntax

```text
public CertificateList getSSHCert();
```

## Remarks

The digital certificate(s) that the server will use during SSH negotiation. Certificates with a private key are required for session authentication and encryption.

These are the server's certificates, and they must be specified before the server starts listening.

 Please refer to the [Certificate](#certificate-type) type for a complete list of fields.

# SSHCompressionAlgorithms Property ([SFTPServer](#sftpserver-class) Class)

The comma-separated list containing all allowable compression algorithms.

## Syntax

```text
public String getSSHCompressionAlgorithms();
public void setSSHCompressionAlgorithms(String SSHCompressionAlgorithms);
```

## Default Value

"none,zlib"

## Remarks

During the Secure Shell (SSH) handshake, this list will be used to negotiate the compression algorithm to be used between the client and server. This list is used for both directions: client to server and server to client. When negotiating algorithms, each side sends a list of all algorithms it supports or allows. The algorithm chosen for each direction is the first algorithm to appear in the sender's list that the receiver supports. Therefore, it is important to list multiple algorithms in preferential order. If no algorithm can be agreed on, the class will raise an error and the connection will be aborted.

At least one supported algorithm must appear in this list. The following compression algorithms are supported by the class:

- zlib
- zlib@openssh.com
- none

# SSHEncryptionAlgorithms Property ([SFTPServer](#sftpserver-class) Class)

The comma-separated list containing all allowable encryption algorithms.

## Syntax

```text
public String getSSHEncryptionAlgorithms();
public void setSSHEncryptionAlgorithms(String SSHEncryptionAlgorithms);
```

## Default Value

"aes256-ctr,aes192-ctr,aes128-ctr,3des-ctr,aes256-gcm@openssh.com,aes128-gcm@openssh.com,chacha20-poly1305@openssh.com"

## Remarks

During the Secure Shell (SSH) handshake, this list will be used to negotiate the encryption algorithm to be used between the client and server. This list is used for both directions: client to server and server to client. When negotiating algorithms, each side sends a list of all algorithms it supports or allows. The algorithm chosen for each direction is the first algorithm to appear in the sender's list that the receiver supports. Therefore, it is important to list multiple algorithms in preferential order. If no algorithm can be agreed on, the class will raise an error and the connection will be aborted.

At least one supported algorithm must appear in this list. The following encryption algorithms are supported by the class:

- aes256-ctr
- aes256-cbc
- aes192-ctr
- aes192-cbc
- aes128-ctr
- aes128-cbc
- 3des-ctr
- 3des-cbc
- cast128-cbc
- blowfish-cbc
- arcfour
- arcfour128
- arcfour256
- aes256-gcm@openssh.com
- aes128-gcm@openssh.com
- chacha20-poly1305@openssh.com

# Config Method ([SFTPServer](#sftpserver-class) Class)

Sets or retrieves a configuration setting.

## Syntax

```text
public String config(String configurationString);
```

## Remarks

Config is a generic method available in every class. It is used to set and retrieve [configuration settings](#config-settings-sftpserver-class) for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these *internal properties* is provided through the Config method.

To set a configuration setting named *PROPERTY*, you must call *Config("PROPERTY=VALUE")*, where *VALUE* is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a [configuration setting](#config-settings-sftpserver-class), you must call *Config("PROPERTY")*. The value will be returned as a string.

# Disconnect Method ([SFTPServer](#sftpserver-class) Class)

This method disconnects the specified client.

## Syntax

```text
public void disconnect(String connectionId);
```

## Remarks

Calling this method will disconnect the client specified by the *ConnectionId* parameter.

# DoEvents Method ([SFTPServer](#sftpserver-class) Class)

This method processes events from the internal message queue.

## Syntax

```text
public void doEvents();
```

## Remarks

When DoEvents is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

# ExchangeKeys Method ([SFTPServer](#sftpserver-class) Class)

Causes the class to exchange a new set of session keys on the specified connection.

## Syntax

```text
public void exchangeKeys(String connectionId);
```

## Remarks

Secure Shell (SSH) key renegotiation can be initiated by either end of an established SSH connection. ExchangeKeys allows the server to start such a renegotiation with the client. During this process, [SSHStatus](#sshstatus-event-sftpserver-class) events will fire with updates about the key negotiation process.

The SSH 2.0 specification recommends that key renegotiation be done once for 2 gigabytes (GB) of data processed by the connection, or once every day. This makes it more difficult to break the security of data-intensive or long-lived connections.

# Reset Method ([SFTPServer](#sftpserver-class) Class)

This method will reset the class.

## Syntax

```text
public void reset();
```

## Remarks

This method will reset the class's properties to their default values.

# SetFileList Method ([SFTPServer](#sftpserver-class) Class)

Sets the file list for a connection during a directory listing request.

## Syntax

```text
public void setFileList(String connectionId, String[] list);
```

## Remarks

SetFileList should be set when a directory listing is requested by the client.

# Shutdown Method ([SFTPServer](#sftpserver-class) Class)

This method shuts down the server.

## Syntax

```text
public void shutdown();
```

## Remarks

This method shuts down the server. Calling this method is equivalent to calling [StopListening](#stoplistening-method-sftpserver-class) and then breaking every client connection by calling [Disconnect](#disconnect-method-sftpserver-class).

# StartListening Method ([SFTPServer](#sftpserver-class) Class)

This method starts listening for incoming connections.

## Syntax

```text
public void startListening();
```

## Remarks

This method begins listening for incoming connections on the port specified by [LocalPort](#localport-property-sftpserver-class). Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call [StopListening](#stoplistening-method-sftpserver-class). To stop listening for new connections and to disconnect all existing clients, call [Shutdown](#shutdown-method-sftpserver-class).

# StopListening Method ([SFTPServer](#sftpserver-class) Class)

This method stops listening for new connections.

## Syntax

```text
public void stopListening();
```

## Remarks

This method stops listening for new connections. After being called, any new connection attempts will be rejected. Calling this method does not disconnect existing connections.

To stop listening and to disconnect all existing clients, call [Shutdown](#shutdown-method-sftpserver-class) instead.

# Connected Event ([SFTPServer](#sftpserver-class) Class)

Fired immediately after a connection completes (or fails).

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void connected(SFTPServerConnectedEvent e) {}
  ...
}

public class SFTPServerConnectedEvent {
  public String connectionId;
  public int statusCode;
  public String description;
  public int certStoreType; //read-write
  public String certStore; //read-write
  public String certPassword; //read-write
  public String certSubject; //read-write
}
```

## Remarks

If the connection is made normally, *StatusCode* is 0, and *Description* is "OK".

If the connection fails, *StatusCode* has the error code returned by the system. *Description* contains a description of this code. The value of *StatusCode* is equal to the value of the system error.

Please refer to the [Error Codes](#trappable-errors-sftpserver-class) section for more information.

*ConnectionId* is the connection Id of the client requesting the connection.

*CertStoreType* is the store type of the alternate certificate to use for this connection. The class supports both public and private keys in a variety of formats. When the *cstAuto* value is used, the class will automatically determine the type. This field can take one of the following values:

```csharp
sftp.SSHCert = new Certificate(CertStoreTypes.cstPKCS11,
                               @"C:\Program Files\OpenSC Project\OpenSC\pkcs11\opensc-pkcs11.dll",
                               "123456", // PIN
                               "CN=cert_subject");
sftp.SSHUser = "test";
sftp.SSHLogon("myhost", 22);
```

```csharp
certmgr.CertStoreType = CertStoreTypes.cstPKCS11;
certmgr.OnCertList += (s, e) => {
  secKeyBlob = e.CertEncoded;
};
certmgr.CertStore = @"C:\Program Files\OpenSC Project\OpenSC\pkcs11\opensc-pkcs11.dll";
certmgr.CertStorePassword = "123456"; // PIN
certmgr.ListStoreCertificates();

sftp.SSHCert = new Certificate(CertStoreTypes.cstPKCS11, secKeyBlob, "123456", "*");
sftp.SSHUser = "test";
sftp.SSHLogon("myhost", 22);
```

|  |  |
| --- | --- |
| 0 (cstUser - default) | For Windows, this specifies that the certificate store is a certificate store owned by the current user. NOTE: This store type is not available in Java. |
| 1 (cstMachine) | For Windows, this specifies that the certificate store is a machine store. NOTE: This store type is not available in Java. |
| 2 (cstPFXFile) | The certificate store is the name of a PFX (PKCS#12) file containing certificates. |
| 3 (cstPFXBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in PFX (PKCS#12) format. |
| 4 (cstJKSFile) | The certificate store is the name of a Java Key Store (JKS) file containing certificates. NOTE: This store type is only available in Java. |
| 5 (cstJKSBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in Java Key Store (JKS) format. NOTE: This store type is only available in Java. |
| 6 (cstPEMKeyFile) | The certificate store is the name of a PEM-encoded file that contains a private key and an optional certificate. |
| 7 (cstPEMKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains a private key and an optional certificate. |
| 8 (cstPublicKeyFile) | The certificate store is the name of a file that contains a PEM- or DER-encoded public key certificate. |
| 9 (cstPublicKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains a PEM- or DER-encoded public key certificate. |
| 10 (cstSSHPublicKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains an SSH-style public key. |
| 11 (cstP7BFile) | The certificate store is the name of a PKCS#7 file containing certificates. |
| 12 (cstP7BBlob) | The certificate store is a string (binary) representing a certificate store in PKCS#7 format. |
| 13 (cstSSHPublicKeyFile) | The certificate store is the name of a file that contains an SSH-style public key. |
| 14 (cstPPKFile) | The certificate store is the name of a file that contains a PPK (PuTTY Private Key). |
| 15 (cstPPKBlob) | The certificate store is a string (binary) that contains a PPK (PuTTY Private Key). |
| 16 (cstXMLFile) | The certificate store is the name of a file that contains a certificate in XML format. |
| 17 (cstXMLBlob) | The certificate store is a string that contains a certificate in XML format. |
| 18 (cstJWKFile) | The certificate store is the name of a file that contains a JWK (JSON Web Key). |
| 19 (cstJWKBlob) | The certificate store is a string that contains a JWK (JSON Web Key). |
| 21 (cstBCFKSFile) | The certificate store is the name of a file that contains a BCFKS (Bouncy Castle FIPS Key Store). NOTE: This store type is only available in Java and .NET. |
| 22 (cstBCFKSBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in BCFKS (Bouncy Castle FIPS Key Store) format. NOTE: This store type is only available in Java and .NET. |
| 23 (cstPKCS11) | The certificate is present on a physical security key accessible via a PKCS#11 interface. To use a security key, create a new [Certificate](#certificate-type) object and pass cstPKCS11 as the [StoreType](#Certificate_f_StoreType), the full path of the PKCS#11 DLL as the [Store](#Certificate_f_Store), and the PIN as the [StorePassword](#Certificate_f_StorePassword). Code Example. SSH Authentication with Security Key (without CertMgr): Alternatively, collect the necessary data using the [CertMgr](CertMgr.md#CertMgr) class by calling the [ListStoreCertificates](CertMgr.md#CertMgr_m_ListStoreCertificates) method after setting the corresponding properties accordingly. The certificate information returned in the [CertList](CertMgr.md#CertMgr_e_CertList) event's CertEncoded parameter may be saved for later use. When using a certificate obtained with this approach, pass the previously saved security key information as the [Store](#Certificate_f_Store) and set [StorePassword](#Certificate_f_StorePassword) to the PIN. Code Example. SSH Authentication with Security Key (with CertMgr): |
| 99 (cstAuto) | The store type is automatically detected from the input data. This setting may be used with both public and private keys and can detect any of the supported formats automatically. |

*CertStore* is the store name or location of the alternate certificate to use for this connection.

 Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

|  |  |
| --- | --- |
| MY | A certificate store holding personal certificates with their associated private keys. |
| CA | Certifying authority certificates. |
| ROOT | Root certificates. |

In Java, the certificate store normally is a file containing certificates and optional private keys.

When the certificate store type is *cstPFXFile*, this property must be set to the name of the file. When the type is *cstPFXBlob*, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

*CertPassword* is the password of the certificate store containing the alternate certificate to use for this connection.

*CertSubject* is the subject of the alternate certificate to use for this connection.

The special value *** matches any subject and will select the first certificate in the store. The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=example@email.com". Common fields and their meanings are as follows:

| Field | Meaning |
| --- | --- |
| CN | Common Name. This is commonly a hostname like www.server.com. |
| O | Organization |
| OU | Organizational Unit |
| L | Locality |
| S | State |
| C | Country |
| E | Email Address |

If a field value contains a comma, it must be quoted.

# ConnectionRequest Event ([SFTPServer](#sftpserver-class) Class)

This event is fired when a request for connection comes from a remote host.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void connectionRequest(SFTPServerConnectionRequestEvent e) {}
  ...
}

public class SFTPServerConnectionRequestEvent {
  public String address;
  public int port;
  public boolean accept; //read-write
}
```

## Remarks

This event indicates an incoming connection. The connection is accepted by default. *Address* and *Port* will contain information about the remote host requesting the inbound connection. If you want to refuse it, you can set the *Accept* parameter to False.

# DirCreate Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client wants to create a new directory.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void dirCreate(SFTPServerDirCreateEvent e) {}
  ...
}

public class SFTPServerDirCreateEvent {
  public String connectionId;
  public String user;
  public String path;
  public int fileType;
  public long fileSize;
  public String fileOwner;
  public String fileGroup;
  public int filePermissions;
  public long fileATime;
  public long fileCreateTime;
  public long fileMTime;
  public int fileAttribBits;
  public int fileAttribBitsValid;
  public String otherAttributes;
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The *Path* parameter specifies the path and name of the new directory.

This event is fired both before and after the directory is created. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

File/Directory Attributes are specified using the following values:

*FileType*: The type of file. Can be one of the following values:

- SSH_FILEXFER_TYPE_REGULAR (1)
- SSH_FILEXFER_TYPE_DIRECTORY (2)
- SSH_FILEXFER_TYPE_SYMLINK (3)
- SSH_FILEXFER_TYPE_SPECIAL (4)
- SSH_FILEXFER_TYPE_UNKNOWN (5)
- SSH_FILEXFER_TYPE_SOCKET (6)
- SSH_FILEXFER_TYPE_CHAR_DEVICE (7)
- SSH_FILEXFER_TYPE_BLOCK_DEVICE (8)
- SSH_FILEXFER_TYPE_FIFO (9)

*FileSize*: The file size, in bytes.

*FileOwner*: The file owner. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like user identifier. V4, V5, and V6 of the secure file transfer protocol (SFTP) allow for an arbitrary string.

*FileGroup*: The file owner group. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like group identifier. V4, V5, and V6 of the SFTP allow for an arbitrary string.

*FilePermissions*: The POSIX-style file permissions.

*FileATime*: The file last-access time, in milliseconds since January 1, 1970, in UTC.

*FileCreateTime*: The file creation time, in milliseconds since January 1, 1970, in UTC.

*FileMTime*: The file last-modified time, in milliseconds since January 1, 1970, in UTC.

*FileAttrBits*: The file attributes, as a combination of the following values:

- SSH_FILEXFER_ATTR_FLAGS_READONLY (0x00000001)
- SSH_FILEXFER_ATTR_FLAGS_SYSTEM (0x00000002)
- SSH_FILEXFER_ATTR_FLAGS_HIDDEN (0x00000004)
- SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE (0x00000008)
- SSH_FILEXFER_ATTR_FLAGS_ARCHIVE (0x00000010)
- SSH_FILEXFER_ATTR_FLAGS_ENCRYPTED (0x00000020)
- SSH_FILEXFER_ATTR_FLAGS_COMPRESSED (0x00000040)
- SSH_FILEXFER_ATTR_FLAGS_SPARSE (0x00000080)
- SSH_FILEXFER_ATTR_FLAGS_APPEND_ONLY (0x00000100)
- SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE (0x00000200)
- SSH_FILEXFER_ATTR_FLAGS_SYNC (0x00000400)
- SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR (0x00000800)

*FileAttrBitsValid*: A mask specifying which bits in *FileAttrBits* are supported by the server.

*OtherAttributes*: A semicolon (;) delimited list of Name=Value pairs of other attributes supported by SFTP. These include the following:

- MIMEType (String)
- AllocationSize (64-bit int)
- ATimeNS (int): ATime nanoseconds
- CreateTimeNS (int): CreateTime nanoseconds
- MTimeNS (int): MTime nanoseconds
- TextHint (8-bit int)
- LinkCount (int)
- UntranslatedName (String)

*FileMimeType*: The MIME type of the file.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# DirList Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client attempts to open a directory for listing.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void dirList(SFTPServerDirListEvent e) {}
  ...
}

public class SFTPServerDirListEvent {
  public String connectionId;
  public String user;
  public String path;
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The DirList event is fired when a secure file transfer protocol (SFTP) client sends an SSH_FXP_OPENDIR request. The *Path* parameter will contain the path of the directory to list.

When necessary, you should call [SetFileList](#setfilelist-method-sftpserver-class) with the list of files and directories in *Path*.

This event is fired both before and after the directory is listed. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# DirRemove Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client wants to delete a directory.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void dirRemove(SFTPServerDirRemoveEvent e) {}
  ...
}

public class SFTPServerDirRemoveEvent {
  public String connectionId;
  public String user;
  public String path;
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The *Path* parameter will specify the directory to delete.

This event is fired both before and after the directory is deleted. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# Disconnected Event ([SFTPServer](#sftpserver-class) Class)

This event is fired when a connection is closed.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void disconnected(SFTPServerDisconnectedEvent e) {}
  ...
}

public class SFTPServerDisconnectedEvent {
  public String connectionId;
  public int statusCode;
  public String description;
}
```

## Remarks

If the connection is broken normally, *StatusCode* is 0, and *Description* is "OK".

If the connection is broken for any other reason, *StatusCode* has the error code returned by the system. *Description* contains a description of this code. The value of *StatusCode* is equal to the value of the system error.

Please refer to the [Error Codes](#trappable-errors-sftpserver-class) section for more information.

# Error Event ([SFTPServer](#sftpserver-class) Class)

Fired when errors occur during data delivery.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void error(SFTPServerErrorEvent e) {}
  ...
}

public class SFTPServerErrorEvent {
  public String connectionId;
  public int errorCode;
  public String description;
}
```

## Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.

*ConnectionId* contains an error code and *Description* contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the [Error Codes](#trappable-errors-sftpserver-class) section.

*ErrorCode* contains an error code and *Description* contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the [Error Codes](#trappable-errors-sftpserver-class) section.

# FileClose Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client attempts to close an open file or directory handle.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void fileClose(SFTPServerFileCloseEvent e) {}
  ...
}

public class SFTPServerFileCloseEvent {
  public String connectionId;
  public String user;
  public String path;
  public String handle;
  public int statusCode; //read-write
}
```

## Remarks

The FileClose event is fired when a secure file transfer protocol (SFTP) client sends an SSH_FXP_CLOSE request. The *Path* parameter will contain the path of the file to close.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# FileOpen Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client wants to open or create a file.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void fileOpen(SFTPServerFileOpenEvent e) {}
  ...
}

public class SFTPServerFileOpenEvent {
  public String connectionId;
  public String user;
  public String path;
  public int desiredAccess;
  public int flags;
  public int fileType;
  public long fileSize;
  public String fileOwner;
  public String fileGroup;
  public int filePermissions;
  public long fileATime;
  public long fileCreateTime;
  public long fileMTime;
  public int fileAttribBits;
  public int fileAttribBitsValid;
  public String otherAttributes;
  public String handle; //read-write
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The *Path* parameter specifies the path and name of the file to open, create. If the operation can be completed successfully, the *Handle* parameter should be set to the handle identifying the opened file.

NOTE: The *Handle* parameter is limited to a 256-byte string. By default, the class will provide an incremental numeric string value for the Handle.

This event is fired both before and after the file is opened. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

The *Flags* parameter specifies file creation and locking options as a bitmask. This may be a combination of the following values:

- SSH_FXF_READ (0x00000001)
- SSH_FXF_WRITE (0x00000002)
- SSH_FXF_APPEND (0x00000004)
- SSH_FXF_CREAT (0x00000008)
- SSH_FXF_TRUNC (0x00000010)
- SSH_FXF_EXCL (0x00000020)

The *DesiredAccess* parameter is a bitmask containing a combination of values from the ace-mask flags (only for protocol versions 4 and up). This may be a combination of the following values:

- ACE4_READ_DATA (0x00000001)
- ACE4_LIST_DIRECTORY (0x00000001)
- ACE4_WRITE_DATA (0x00000002)
- ACE4_ADD_FILE (0x00000002)
- ACE4_APPEND_DATA (0x00000004)
- ACE4_ADD_SUBDIRECTORY (0x00000004)
- ACE4_READ_NAMED_ATTRS (0x00000008)
- ACE4_WRITE_NAMED_ATTRS (0x00000010)
- ACE4_EXECUTE (0x00000020)
- ACE4_DELETE_CHILD (0x00000040)
- ACE4_READ_ATTRIBUTES (0x00000080)
- ACE4_WRITE_ATTRIBUTES (0x00000100)
- ACE4_DELETE (0x00010000)
- ACE4_READ_ACL (0x00020000)
- ACE4_WRITE_ACL (0x00040000)
- ACE4_WRITE_OWNER (0x00080000)
- ACE4_SYNCHRONIZE (0x00100000)

 Please see RFC 3010 for more information on the semantics of these values.

File/Directory Attributes are specified using the following values:

*FileType*: The type of file. Can be one of the following values:

- SSH_FILEXFER_TYPE_REGULAR (1)
- SSH_FILEXFER_TYPE_DIRECTORY (2)
- SSH_FILEXFER_TYPE_SYMLINK (3)
- SSH_FILEXFER_TYPE_SPECIAL (4)
- SSH_FILEXFER_TYPE_UNKNOWN (5)
- SSH_FILEXFER_TYPE_SOCKET (6)
- SSH_FILEXFER_TYPE_CHAR_DEVICE (7)
- SSH_FILEXFER_TYPE_BLOCK_DEVICE (8)
- SSH_FILEXFER_TYPE_FIFO (9)

*FileSize*: The file size, in bytes.

*FileOwner*: The file owner. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like user identifier. V4, V5, and V6 of the secure file transfer protocol (SFTP) allow for an arbitrary string.

*FileGroup*: The file owner group. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like group identifier. V4, V5, and V6 of the SFTP allow for an arbitrary string.

*FilePermissions*: The POSIX-style file permissions.

*FileATime*: The file last-access time, in milliseconds since January 1, 1970, in UTC.

*FileCreateTime*: The file creation time, in milliseconds since January 1, 1970, in UTC.

*FileMTime*: The file last-modified time, in milliseconds since January 1, 1970, in UTC.

*FileAttrBits*: The file attributes, as a combination of the following values:

- SSH_FILEXFER_ATTR_FLAGS_READONLY (0x00000001)
- SSH_FILEXFER_ATTR_FLAGS_SYSTEM (0x00000002)
- SSH_FILEXFER_ATTR_FLAGS_HIDDEN (0x00000004)
- SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE (0x00000008)
- SSH_FILEXFER_ATTR_FLAGS_ARCHIVE (0x00000010)
- SSH_FILEXFER_ATTR_FLAGS_ENCRYPTED (0x00000020)
- SSH_FILEXFER_ATTR_FLAGS_COMPRESSED (0x00000040)
- SSH_FILEXFER_ATTR_FLAGS_SPARSE (0x00000080)
- SSH_FILEXFER_ATTR_FLAGS_APPEND_ONLY (0x00000100)
- SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE (0x00000200)
- SSH_FILEXFER_ATTR_FLAGS_SYNC (0x00000400)
- SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR (0x00000800)

*FileAttrBitsValid*: A mask specifying which bits in *FileAttrBits* are supported by the server.

*OtherAttributes*: A semicolon (;) delimited list of Name=Value pairs of other attributes supported by SFTP. These include the following:

- MIMEType (String)
- AllocationSize (64-bit int)
- ATimeNS (int): ATime nanoseconds
- CreateTimeNS (int): CreateTime nanoseconds
- MTimeNS (int): MTime nanoseconds
- TextHint (8-bit int)
- LinkCount (int)
- UntranslatedName (String)

*FileMimeType*: The MIME type of the file.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# FileRead Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client wants to read from an open file.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void fileRead(SFTPServerFileReadEvent e) {}
  ...
}

public class SFTPServerFileReadEvent {
  public String connectionId;
  public String user;
  public String handle;
  public long fileOffset;
  public int length;
  public int statusCode; //read-write
}
```

## Remarks

The *Handle* parameter identifies an open file on the server. *FileOffset* specifies the position from which to read data. *Length* specifies how much data to read. The data read should be set to through [FileData](#SFTPConnection_f_FileData)

When processing a read request, the server should attempt to read at most *Length* bytes, but it is okay to read less than *Length* bytes as well, if no more data are available.

When there are no more data to be read from the file, set *StatusCode* to SSH_FXS_EOF.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# FileRemove Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client wants to delete a file.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void fileRemove(SFTPServerFileRemoveEvent e) {}
  ...
}

public class SFTPServerFileRemoveEvent {
  public String connectionId;
  public String user;
  public String path;
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The *Path* parameter will specify the file to delete.

This event is fired both before and after the file is removed. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# FileRename Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client wants to rename a file.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void fileRename(SFTPServerFileRenameEvent e) {}
  ...
}

public class SFTPServerFileRenameEvent {
  public String connectionId;
  public String user;
  public String path;
  public String newPath;
  public int flags;
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The *Path* parameter will specify the file to rename and *NewPath* will specify the new name. The *Flags* parameter will be a bit mask of the values SSH_FXF_RENAME_OVERWRITE (0x00000001), SSH_FXF_RENAME_ATOMIC (0x00000002), and SSH_FXF_RENAME_NATIVE (0x00000004).

This event is fired both before and after the file is renamed. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# FileWrite Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client wants to write to an open file.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void fileWrite(SFTPServerFileWriteEvent e) {}
  ...
}

public class SFTPServerFileWriteEvent {
  public String connectionId;
  public String user;
  public String handle;
  public long fileOffset;
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The *Handle* parameter identifies an open file on the server. *FileOffset* specifies the position at which to write data. The data to write can be retrieved through [FileData](#SFTPConnection_f_FileData)

This event is fired both before and after the file is written. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# GetAttributes Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client needs to get file information.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void getAttributes(SFTPServerGetAttributesEvent e) {}
  ...
}

public class SFTPServerGetAttributesEvent {
  public String connectionId;
  public String user;
  public String path;
  public int flags;
  public int fileType; //read-write
  public long fileSize; //read-write
  public String fileOwner; //read-write
  public String fileGroup; //read-write
  public int filePermissions; //read-write
  public long fileATime; //read-write
  public long fileCreateTime; //read-write
  public long fileMTime; //read-write
  public int fileAttribBits; //read-write
  public int fileAttribBitsValid; //read-write
  public String otherAttributes; //read-write
  public int statusCode; //read-write
}
```

## Remarks

The GetAttributes event fires when a secure file transfer protocol (SFTP) client sends an SSH_FXP_STAT, SSH_FXP_LSTAT, or SSH_FXP_FSTAT request. *Path* is the file path. *Flags* specifies the set of file attributes the client is interested in.

File/Directory Attributes are specified using the following values:

*FileType*: The type of file. Can be one of the following values:

- SSH_FILEXFER_TYPE_REGULAR (1)
- SSH_FILEXFER_TYPE_DIRECTORY (2)
- SSH_FILEXFER_TYPE_SYMLINK (3)
- SSH_FILEXFER_TYPE_SPECIAL (4)
- SSH_FILEXFER_TYPE_UNKNOWN (5)
- SSH_FILEXFER_TYPE_SOCKET (6)
- SSH_FILEXFER_TYPE_CHAR_DEVICE (7)
- SSH_FILEXFER_TYPE_BLOCK_DEVICE (8)
- SSH_FILEXFER_TYPE_FIFO (9)

*FileSize*: The file size, in bytes.

*FileOwner*: The file owner. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like user identifier. V4, V5, and V6 of the secure file transfer protocol (SFTP) allow for an arbitrary string.

*FileGroup*: The file owner group. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like group identifier. V4, V5, and V6 of the SFTP allow for an arbitrary string.

*FilePermissions*: The POSIX-style file permissions.

*FileATime*: The file last-access time, in milliseconds since January 1, 1970, in UTC.

*FileCreateTime*: The file creation time, in milliseconds since January 1, 1970, in UTC.

*FileMTime*: The file last-modified time, in milliseconds since January 1, 1970, in UTC.

*FileAttrBits*: The file attributes, as a combination of the following values:

- SSH_FILEXFER_ATTR_FLAGS_READONLY (0x00000001)
- SSH_FILEXFER_ATTR_FLAGS_SYSTEM (0x00000002)
- SSH_FILEXFER_ATTR_FLAGS_HIDDEN (0x00000004)
- SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE (0x00000008)
- SSH_FILEXFER_ATTR_FLAGS_ARCHIVE (0x00000010)
- SSH_FILEXFER_ATTR_FLAGS_ENCRYPTED (0x00000020)
- SSH_FILEXFER_ATTR_FLAGS_COMPRESSED (0x00000040)
- SSH_FILEXFER_ATTR_FLAGS_SPARSE (0x00000080)
- SSH_FILEXFER_ATTR_FLAGS_APPEND_ONLY (0x00000100)
- SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE (0x00000200)
- SSH_FILEXFER_ATTR_FLAGS_SYNC (0x00000400)
- SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR (0x00000800)

*FileAttrBitsValid*: A mask specifying which bits in *FileAttrBits* are supported by the server.

*OtherAttributes*: A semicolon (;) delimited list of Name=Value pairs of other attributes supported by SFTP. These include the following:

- MIMEType (String)
- AllocationSize (64-bit int)
- ATimeNS (int): ATime nanoseconds
- CreateTimeNS (int): CreateTime nanoseconds
- MTimeNS (int): MTime nanoseconds
- TextHint (8-bit int)
- LinkCount (int)
- UntranslatedName (String)

*FileMimeType*: The MIME type of the file.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# Log Event ([SFTPServer](#sftpserver-class) Class)

Fired once for each log message.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void log(SFTPServerLogEvent e) {}
  ...
}

public class SFTPServerLogEvent {
  public String connectionId;
  public int logLevel;
  public String message;
  public String logType;
}
```

## Remarks

Fired once for each log message generated by the class. The verbosity is controlled by the [LogLevel](#LogLevel) setting.

*LogLevel* indicates the detail level of the message. Possible values are as follows:

|  |  |
| --- | --- |
| 0 (None) | No messages are logged. |
| 1 (Info - Default) | Informational events such as Secure Shell (SSH) handshake messages are logged. |
| 2 (Verbose) | Detailed data such as individual packet information are logged. |
| 3 (Debug) | Debug data including all relevant sent and received bytes are logged. |

*Message* is the log message.

*LogType* is reserved for future use.

*ConnectionId* identifies the connection to which the log message applies.

# ResolvePath Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client attempts to canonicalize a path.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void resolvePath(SFTPServerResolvePathEvent e) {}
  ...
}

public class SFTPServerResolvePathEvent {
  public String connectionId;
  public String user;
  public String originalPath;
  public int controlFlags;
  public String realPath; //read-write
  public int statusCode; //read-write
}
```

## Remarks

The ResolvePath event is fired when a secure file transfer protocol (SFTP) client sends an SSH_FXP_REALPATH request. The *OriginalPath* parameter will contain the path the client wants to canonicalize. *ControlFlags* can have one of the following values:

|  |  |
| --- | --- |
| SSH_FXP_REALPATH_NO_CHECK (0x00000001) | Server should not check if the path exists. |
| SSH_FXP_REALPATH_STAT_IF (0x00000002) | Server should return the file/directory attributes if the path exists and is accessible, but otherwise should not fail. |
| SSH_FXP_REALPATH_STAT_ALWAYS (0x00000003) | Server should return the file/directory attributes if the path exists and is accessible, but otherwise will fail with an error. |

*RealPath* should be set to the resulting canonicalized path, and *StatusCode* should be set to indicate the success or failure of the operation to the client.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# SetAttributes Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client attempts to set file or directory attributes.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void setAttributes(SFTPServerSetAttributesEvent e) {}
  ...
}

public class SFTPServerSetAttributesEvent {
  public String connectionId;
  public String user;
  public String path;
  public int fileType;
  public long fileSize;
  public String fileOwner;
  public String fileGroup;
  public int filePermissions;
  public long fileATime;
  public long fileCreateTime;
  public long fileMTime;
  public int fileAttribBits;
  public int fileAttribBitsValid;
  public String otherAttributes;
  public boolean beforeExec;
  public int statusCode; //read-write
}
```

## Remarks

The SetAttributes event is fired when a secure file transfer protocol (SFTP) client sends an SSH_FXP_SETSTAT, SSH_FXP_FSETSTAT, or SSH_FXP_FSTAT request. *Path* is the path of the file or directory the client wants to set attributes for.

This event is fired both before and after the attributes are set. The *BeforeExec* parameter is *True* before the operation has been executed and *False* otherwise. Handling this event before execution of the operation provides an opportunity to add custom logic that may prevent or deny the operation. Handling this event after execution of the operation provides an opportunity to report any errors that may have occurred during the operation.

File/Directory Attributes are specified using the following values:

*FileType*: The type of file. Can be one of the following values:

- SSH_FILEXFER_TYPE_REGULAR (1)
- SSH_FILEXFER_TYPE_DIRECTORY (2)
- SSH_FILEXFER_TYPE_SYMLINK (3)
- SSH_FILEXFER_TYPE_SPECIAL (4)
- SSH_FILEXFER_TYPE_UNKNOWN (5)
- SSH_FILEXFER_TYPE_SOCKET (6)
- SSH_FILEXFER_TYPE_CHAR_DEVICE (7)
- SSH_FILEXFER_TYPE_BLOCK_DEVICE (8)
- SSH_FILEXFER_TYPE_FIFO (9)

*FileSize*: The file size, in bytes.

*FileOwner*: The file owner. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like user identifier. V4, V5, and V6 of the secure file transfer protocol (SFTP) allow for an arbitrary string.

*FileGroup*: The file owner group. If the ProtocolVersion configuration option is "3" (default), this field should be a numeric Unix-like group identifier. V4, V5, and V6 of the SFTP allow for an arbitrary string.

*FilePermissions*: The POSIX-style file permissions.

*FileATime*: The file last-access time, in milliseconds since January 1, 1970, in UTC.

*FileCreateTime*: The file creation time, in milliseconds since January 1, 1970, in UTC.

*FileMTime*: The file last-modified time, in milliseconds since January 1, 1970, in UTC.

*FileAttrBits*: The file attributes, as a combination of the following values:

- SSH_FILEXFER_ATTR_FLAGS_READONLY (0x00000001)
- SSH_FILEXFER_ATTR_FLAGS_SYSTEM (0x00000002)
- SSH_FILEXFER_ATTR_FLAGS_HIDDEN (0x00000004)
- SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE (0x00000008)
- SSH_FILEXFER_ATTR_FLAGS_ARCHIVE (0x00000010)
- SSH_FILEXFER_ATTR_FLAGS_ENCRYPTED (0x00000020)
- SSH_FILEXFER_ATTR_FLAGS_COMPRESSED (0x00000040)
- SSH_FILEXFER_ATTR_FLAGS_SPARSE (0x00000080)
- SSH_FILEXFER_ATTR_FLAGS_APPEND_ONLY (0x00000100)
- SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE (0x00000200)
- SSH_FILEXFER_ATTR_FLAGS_SYNC (0x00000400)
- SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR (0x00000800)

*FileAttrBitsValid*: A mask specifying which bits in *FileAttrBits* are supported by the server.

*OtherAttributes*: A semicolon (;) delimited list of Name=Value pairs of other attributes supported by SFTP. These include the following:

- MIMEType (String)
- AllocationSize (64-bit int)
- ATimeNS (int): ATime nanoseconds
- CreateTimeNS (int): CreateTime nanoseconds
- MTimeNS (int): MTime nanoseconds
- TextHint (8-bit int)
- LinkCount (int)
- UntranslatedName (String)

*FileMimeType*: The MIME type of the file.

Valid status codes are as follows:

- SSH_FX_OK 0
- SSH_FX_EOF 1
- SSH_FX_NO_SUCH_FILE 2
- SSH_FX_PERMISSION_DENIED 3
- SSH_FX_FAILURE 4
- SSH_FX_BAD_MESSAGE 5
- SSH_FX_NO_CONNECTION 6
- SSH_FX_CONNECTION_LOST 7
- SSH_FX_OP_UNSUPPORTED 8
- SSH_FX_INVALID_HANDLE 9
- SSH_FX_NO_SUCH_PATH 10
- SSH_FX_FILE_ALREADY_EXISTS 11
- SSH_FX_WRITE_PROTECT 12
- SSH_FX_NO_MEDIA 13
- SSH_FX_NO_SPACE_ON_FILESYSTEM 14
- SSH_FX_QUOTA_EXCEEDED 15
- SSH_FX_UNKNOWN_PRINCIPAL 16
- SSH_FX_LOCK_CONFLICT 17
- SSH_FX_DIR_NOT_EMPTY 18
- SSH_FX_NOT_A_DIRECTORY 19
- SSH_FX_INVALID_FILENAME 20
- SSH_FX_LINK_LOOP 21
- SSH_FX_CANNOT_DELETE 22
- SSH_FX_INVALID_PARAMETER 23
- SSH_FX_FILE_IS_A_DIRECTORY 24
- SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
- SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
- SSH_FX_DELETE_PENDING 27
- SSH_FX_FILE_CORRUPT 28
- SSH_FX_OWNER_INVALID 29
- SSH_FX_GROUP_INVALID 30
- SSH_FX_NO_MATCHING_BYTE_RANGE_LOCK 31

# SSHStatus Event ([SFTPServer](#sftpserver-class) Class)

Fired to track the progress of the secure connection.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void SSHStatus(SFTPServerSSHStatusEvent e) {}
  ...
}

public class SFTPServerSSHStatusEvent {
  public String connectionId;
  public String message;
}
```

## Remarks

This event is fired for informational and logging purposes only and is used to track the progress of the connection.

# SSHUserAuthRequest Event ([SFTPServer](#sftpserver-class) Class)

Fired when a client attempts to authenticate a connection.

## Syntax

```text
public class DefaultSFTPServerEventListener implements SFTPServerEventListener {
  ...
  public void SSHUserAuthRequest(SFTPServerSSHUserAuthRequestEvent e) {}
  ...
}

public class SFTPServerSSHUserAuthRequestEvent {
  public String connectionId;
  public String user;
  public String service;
  public String authMethod;
  public String authParam;
  public boolean accept; //read-write
  public boolean partialSuccess; //read-write
  public String availableMethods; //read-write
  public String homeDir; //read-write
  public String keyAlgorithm;
}
```

## Remarks

The SSHUserAuthRequest event fires when a Secure Shell (SSH) client attempts to authenticate itself on a particular connection. *ConnectionId* will identify the connection being authenticated. *User* will be the name of the account requesting authentication, and *Service* will contain the name of the service the client is wishing to access.

*AuthMethod* will denote which method the client is attempting to use to authenticate itself. *AuthParam* will contain the value of the authentication token used by the client. If the token is acceptable, you may set *Accept* to True to allow the SFTPServer to authenticate the client. If it is not, set *Accept* to False.

Connecting clients will initially attempt authentication with an *AuthMethod* of "none". This is done with the expectation that the request will fail and the server will send a list of supported methods back to the client. In your implementation, check the *AuthMethod* parameter; if it is "none", you should set *AvailableMethods* and reject the request. The client will select one of the available methods and reauthenticate.

You may set *AvailableMethods* to a comma-delimited string of authentication methods that are available for the user. This list will be sent back to the client so that it may perform further authentication attempts.

The following is a list of methods implemented by the class:

|  |  |
| --- | --- |
| none | This authentication method is used by most Secure Shell (SSH) clients to obtain the list of authentication methods available for the user's account. In most cases, you should not accept a request using this authentication method. |
| password | AuthParam will contain the user-supplied password. If the password is correct, set Accept to True. |
| publickey | AuthParam will contain an SSH2 public key blob. If the user's public key is acceptable, set Accept or PartialSuccess to true. The class will then handle verifying the digital signature and will respond to the client accordingly. |
| keyboard-interactive | SSHUserAuthRequest will fire multiple times for keyboard-interactive authentication: It will fire once for each response sent by the client in the SSH_MSG_USERAUTH_INFO_RESPONSE packet (one time for each prompt specified by the daemon). The index of each response will be specified as a suffix in AuthMethod, with AuthParam containing the response to the corresponding prompt (e.g., keyboard-interactive-1, keyboard-interactive-2, and so on). Finally, SSHUserAuthRequest will fire one last time with AuthMethod set to "keyboard-interactive" and AuthParam set to an empty string. The daemon must set Accept to True every time to allow the authentication process to succeed. |

If the user authentication succeeds, you may set *HomeDir* to the virtual path representing the initial directory for the user. If not set, the initial directory will be [RootDirectory](#rootdirectory-property-sftpserver-class).

The *PartialSuccess* parameter is used only when multifactor authentication is needed. To implement multifactor authentication when this event fires, first verify the *AuthParam* for the given *AuthMethod*. If accepted, set *PartialSuccess* to True and *Accept* to False. The client should then send the authentication request for a different form of authentication specified in *AvailableMethods*. You may continue to set *PartialSuccess* to True until all authentication requirements are satisfied. Once all requirements are satisfied set *Accept* to True.

*KeyAlgorithm* holds the signing algorithm used when the client attempts public key authentication. Possible values are as follows:

- ssh-rsa
- rsa-sha2-256
- rsa-sha2-512
- ssh-dss
- ecdsa-sha2-nistp256
- ecdsa-sha2-nistp384
- ecdsa-sha2-nistp521
- x509v3-sign-rsa
- x509v3-sign-dss

NOTE: Processing long-running requests, including sending channel data, inside this event may cause the underlying transport to stop processing Secure Shell (SSH) data until the event returns. To prevent this from happening, all requests should be processed asynchronously in a separate thread outside of this event.

# Certificate Type

This is the digital certificate being used.

## Remarks

This type describes the current digital certificate. The certificate may be a public or private key. The fields are used to identify or select certificates.

The following fields are available:

- [EffectiveDate](#Certificate_f_EffectiveDate)

- [ExpirationDate](#Certificate_f_ExpirationDate)

- [ExtendedKeyUsage](#Certificate_f_ExtendedKeyUsage)

- [Fingerprint](#Certificate_f_Fingerprint)

- [FingerprintSHA1](#Certificate_f_FingerprintSHA1)

- [FingerprintSHA256](#Certificate_f_FingerprintSHA256)

- [Issuer](#Certificate_f_Issuer)

- [KeyPassword](#Certificate_f_KeyPassword)

- [PrivateKey](#Certificate_f_PrivateKey)

- [PrivateKeyAvailable](#Certificate_f_PrivateKeyAvailable)

- [PrivateKeyContainer](#Certificate_f_PrivateKeyContainer)

- [PublicKey](#Certificate_f_PublicKey)

- [PublicKeyAlgorithm](#Certificate_f_PublicKeyAlgorithm)

- [PublicKeyLength](#Certificate_f_PublicKeyLength)

- [SerialNumber](#Certificate_f_SerialNumber)

- [SignatureAlgorithm](#Certificate_f_SignatureAlgorithm)

- [Store](#Certificate_f_Store)

- [StorePassword](#Certificate_f_StorePassword)

- [StoreType](#Certificate_f_StoreType)

- [SubjectAltNames](#Certificate_f_SubjectAltNames)

- [ThumbprintMD5](#Certificate_f_ThumbprintMD5)

- [ThumbprintSHA1](#Certificate_f_ThumbprintSHA1)

- [ThumbprintSHA256](#Certificate_f_ThumbprintSHA256)

- [Usage](#Certificate_f_Usage)

- [UsageFlags](#Certificate_f_UsageFlags)

- [Version](#Certificate_f_Version)

- [Subject](#Certificate_f_Subject)

- [Encoded](#Certificate_f_Encoded)

## Fields

 **EffectiveDate** *String (read-only)*
*Default Value: ""*

The date on which this certificate becomes valid. Before this date, it is not valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2000 15:00:00.

 **ExpirationDate** *String (read-only)*
*Default Value: ""*

The date on which the certificate expires. After this date, the certificate will no longer be valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2001 15:00:00.

 **ExtendedKeyUsage** *String (read-only)*
*Default Value: ""*

A comma-delimited list of extended key usage identifiers. These are the same as ASN.1 object identifiers (OIDs).

 **Fingerprint** *String (read-only)*
*Default Value: ""*

The hex-encoded, 16-byte MD5 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: *bc:2a:72:af:fe:58:17:43:7a:5f:ba:5a:7c:90:f7:02*

 **FingerprintSHA1** *String (read-only)*
*Default Value: ""*

The hex-encoded, 20-byte SHA-1 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: *30:7b:fa:38:65:83:ff:da:b4:4e:07:3f:17:b8:a4:ed:80:be:ff:84*

 **FingerprintSHA256** *String (read-only)*
*Default Value: ""*

The hex-encoded, 32-byte SHA-256 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: *6a:80:5c:33:a9:43:ea:b0:96:12:8a:64:96:30:ef:4a:8a:96:86:ce:f4:c7:be:10:24:8e:2b:60:9e:f3:59:53*

 **Issuer** *String (read-only)*
*Default Value: ""*

The issuer of the certificate. This field contains a string representation of the name of the issuing authority for the certificate.

 **KeyPassword** *String*
*Default Value: ""*

The password for the certificate's private key (if any).

Some certificate stores may individually protect certificates' private keys, separate from the standard protection offered by the [StorePassword](#Certificate_f_StorePassword). This field can be used to read such password-protected private keys.

NOTE: This property defaults to the value of [StorePassword](#Certificate_f_StorePassword). To clear it, you must set the property to the empty string (""). It can be set at any time, but when the private key's password is different from the store's password, then it must be set before calling [PrivateKey](#Certificate_f_PrivateKey).

 **PrivateKey** *String (read-only)*
*Default Value: ""*

The private key of the certificate (if available). The key is provided as PEM/Base64-encoded data.

NOTE: The [PrivateKey](#Certificate_f_PrivateKey) may be available but not exportable. In this case, [PrivateKey](#Certificate_f_PrivateKey) returns an empty string.

 **PrivateKeyAvailable** *boolean (read-only)*
*Default Value: False*

Whether a [PrivateKey](#Certificate_f_PrivateKey) is available for the selected certificate. If [PrivateKeyAvailable](#Certificate_f_PrivateKeyAvailable) is True, the certificate may be used for authentication purposes (e.g., server authentication).

 **PrivateKeyContainer** *String (read-only)*
*Default Value: ""*

The name of the [PrivateKey](#Certificate_f_PrivateKey) container for the certificate (if available). This functionality is available only on Windows platforms.

 **PublicKey** *String (read-only)*
*Default Value: ""*

The public key of the certificate. The key is provided as PEM/Base64-encoded data.

 **PublicKeyAlgorithm** *String (read-only)*
*Default Value: ""*

The textual description of the certificate's public key algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_DH") or an object identifier (OID) string representing the algorithm.

 **PublicKeyLength** *int (read-only)*
*Default Value: 0*

The length of the certificate's public key (in bits). Common values are 512, 1024, and 2048.

 **SerialNumber** *String (read-only)*
*Default Value: ""*

The serial number of the certificate encoded as a string. The number is encoded as a series of hexadecimal digits, with each pair representing a byte of the serial number.

 **SignatureAlgorithm** *String (read-only)*
*Default Value: ""*

The text description of the certificate's signature algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_MD5RSA") or an object identifier (OID) string representing the algorithm.

 **Store** *String*
*Default Value: "MY"*

The name of the certificate store for the client certificate.

The [StoreType](#Certificate_f_StoreType) field denotes the type of the certificate store specified by [Store](#Certificate_f_Store). If the store is password-protected, specify the password in [StorePassword](#Certificate_f_StorePassword).

[Store](#Certificate_f_Store) is used in conjunction with the [Subject](#Certificate_f_Subject) field to specify client certificates. If [Store](#Certificate_f_Store) has a value, and [Subject](#Certificate_f_Subject) or [Encoded](#Certificate_f_Encoded) is set, a search for a certificate is initiated. Please see the [Subject](#Certificate_f_Subject) field for details.

 Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

|  |  |
| --- | --- |
| MY | A certificate store holding personal certificates with their associated private keys. |
| CA | Certifying authority certificates. |
| ROOT | Root certificates. |

In Java, the certificate store normally is a file containing certificates and optional private keys.

When the certificate store type is *cstPFXFile*, this property must be set to the name of the file. When the type is *cstPFXBlob*, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

 **StoreB** *byte[]*
*Default Value: "MY"*

The name of the certificate store for the client certificate.

The [StoreType](#Certificate_f_StoreType) field denotes the type of the certificate store specified by [Store](#Certificate_f_Store). If the store is password-protected, specify the password in [StorePassword](#Certificate_f_StorePassword).

[Store](#Certificate_f_Store) is used in conjunction with the [Subject](#Certificate_f_Subject) field to specify client certificates. If [Store](#Certificate_f_Store) has a value, and [Subject](#Certificate_f_Subject) or [Encoded](#Certificate_f_Encoded) is set, a search for a certificate is initiated. Please see the [Subject](#Certificate_f_Subject) field for details.

 Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

|  |  |
| --- | --- |
| MY | A certificate store holding personal certificates with their associated private keys. |
| CA | Certifying authority certificates. |
| ROOT | Root certificates. |

In Java, the certificate store normally is a file containing certificates and optional private keys.

When the certificate store type is *cstPFXFile*, this property must be set to the name of the file. When the type is *cstPFXBlob*, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

 **StorePassword** *String*
*Default Value: ""*

If the type of certificate store requires a password, this field is used to specify the password needed to open the certificate store.

 **StoreType** *int*
*Default Value: 0*

The type of certificate store for this certificate.

 The class supports both public and private keys in a variety of formats. When the *cstAuto* value is used, the class will automatically determine the type. This field can take one of the following values:

```csharp
sftp.SSHCert = new Certificate(CertStoreTypes.cstPKCS11,
                               @"C:\Program Files\OpenSC Project\OpenSC\pkcs11\opensc-pkcs11.dll",
                               "123456", // PIN
                               "CN=cert_subject");
sftp.SSHUser = "test";
sftp.SSHLogon("myhost", 22);
```

```csharp
certmgr.CertStoreType = CertStoreTypes.cstPKCS11;
certmgr.OnCertList += (s, e) => {
  secKeyBlob = e.CertEncoded;
};
certmgr.CertStore = @"C:\Program Files\OpenSC Project\OpenSC\pkcs11\opensc-pkcs11.dll";
certmgr.CertStorePassword = "123456"; // PIN
certmgr.ListStoreCertificates();

sftp.SSHCert = new Certificate(CertStoreTypes.cstPKCS11, secKeyBlob, "123456", "*");
sftp.SSHUser = "test";
sftp.SSHLogon("myhost", 22);
```

|  |  |
| --- | --- |
| 0 (cstUser - default) | For Windows, this specifies that the certificate store is a certificate store owned by the current user. NOTE: This store type is not available in Java. |
| 1 (cstMachine) | For Windows, this specifies that the certificate store is a machine store. NOTE: This store type is not available in Java. |
| 2 (cstPFXFile) | The certificate store is the name of a PFX (PKCS#12) file containing certificates. |
| 3 (cstPFXBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in PFX (PKCS#12) format. |
| 4 (cstJKSFile) | The certificate store is the name of a Java Key Store (JKS) file containing certificates. NOTE: This store type is only available in Java. |
| 5 (cstJKSBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in Java Key Store (JKS) format. NOTE: This store type is only available in Java. |
| 6 (cstPEMKeyFile) | The certificate store is the name of a PEM-encoded file that contains a private key and an optional certificate. |
| 7 (cstPEMKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains a private key and an optional certificate. |
| 8 (cstPublicKeyFile) | The certificate store is the name of a file that contains a PEM- or DER-encoded public key certificate. |
| 9 (cstPublicKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains a PEM- or DER-encoded public key certificate. |
| 10 (cstSSHPublicKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains an SSH-style public key. |
| 11 (cstP7BFile) | The certificate store is the name of a PKCS#7 file containing certificates. |
| 12 (cstP7BBlob) | The certificate store is a string (binary) representing a certificate store in PKCS#7 format. |
| 13 (cstSSHPublicKeyFile) | The certificate store is the name of a file that contains an SSH-style public key. |
| 14 (cstPPKFile) | The certificate store is the name of a file that contains a PPK (PuTTY Private Key). |
| 15 (cstPPKBlob) | The certificate store is a string (binary) that contains a PPK (PuTTY Private Key). |
| 16 (cstXMLFile) | The certificate store is the name of a file that contains a certificate in XML format. |
| 17 (cstXMLBlob) | The certificate store is a string that contains a certificate in XML format. |
| 18 (cstJWKFile) | The certificate store is the name of a file that contains a JWK (JSON Web Key). |
| 19 (cstJWKBlob) | The certificate store is a string that contains a JWK (JSON Web Key). |
| 21 (cstBCFKSFile) | The certificate store is the name of a file that contains a BCFKS (Bouncy Castle FIPS Key Store). NOTE: This store type is only available in Java and .NET. |
| 22 (cstBCFKSBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in BCFKS (Bouncy Castle FIPS Key Store) format. NOTE: This store type is only available in Java and .NET. |
| 23 (cstPKCS11) | The certificate is present on a physical security key accessible via a PKCS#11 interface. To use a security key, create a new [Certificate](#certificate-type) object and pass cstPKCS11 as the [StoreType](#Certificate_f_StoreType), the full path of the PKCS#11 DLL as the [Store](#Certificate_f_Store), and the PIN as the [StorePassword](#Certificate_f_StorePassword). Code Example. SSH Authentication with Security Key (without CertMgr): Alternatively, collect the necessary data using the [CertMgr](CertMgr.md#CertMgr) class by calling the [ListStoreCertificates](CertMgr.md#CertMgr_m_ListStoreCertificates) method after setting the corresponding properties accordingly. The certificate information returned in the [CertList](CertMgr.md#CertMgr_e_CertList) event's CertEncoded parameter may be saved for later use. When using a certificate obtained with this approach, pass the previously saved security key information as the [Store](#Certificate_f_Store) and set [StorePassword](#Certificate_f_StorePassword) to the PIN. Code Example. SSH Authentication with Security Key (with CertMgr): |
| 99 (cstAuto) | The store type is automatically detected from the input data. This setting may be used with both public and private keys and can detect any of the supported formats automatically. |

 **SubjectAltNames** *String (read-only)*
*Default Value: ""*

Comma-separated lists of alternative subject names for the certificate.

 **ThumbprintMD5** *String (read-only)*
*Default Value: ""*

The MD5 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

 **ThumbprintSHA1** *String (read-only)*
*Default Value: ""*

The SHA-1 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

 **ThumbprintSHA256** *String (read-only)*
*Default Value: ""*

The SHA-256 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

 **Usage** *String (read-only)*
*Default Value: ""*

The text description of [UsageFlags](#Certificate_f_UsageFlags).

This value will be one or more of the following strings and will be separated by commas:

- Digital Signature
- Non-Repudiation
- Key Encipherment
- Data Encipherment
- Key Agreement
- Certificate Signing
- CRL Signing
- Encipher Only

If the provider is OpenSSL, the value is a comma-separated list of X.509 certificate extension names.

 **UsageFlags** *int (read-only)*
*Default Value: 0*

The flags that show intended use for the certificate. The value of [UsageFlags](#Certificate_f_UsageFlags) is a combination of the following flags:

|  |  |
| --- | --- |
| 0x80 | Digital Signature |
| 0x40 | Non-Repudiation |
| 0x20 | Key Encipherment |
| 0x10 | Data Encipherment |
| 0x08 | Key Agreement |
| 0x04 | Certificate Signing |
| 0x02 | CRL Signing |
| 0x01 | Encipher Only |

Please see the [Usage](#Certificate_f_Usage) field for a text representation of [UsageFlags](#Certificate_f_UsageFlags).

This functionality currently is not available when the provider is OpenSSL.

 **Version** *String (read-only)*
*Default Value: ""*

The certificate's version number. The possible values are the strings "V1", "V2", and "V3".

 **Subject** *String*
*Default Value: ""*

The subject of the certificate used for client authentication.

This field will be populated with the full subject of the loaded certificate. When loading a certificate, the subject is used to locate the certificate in the store.

If an exact match is not found, the store is searched for subjects containing the value of the property.

If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks a random certificate in the certificate store.

The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=example@email.com". Common fields and their meanings are as follows:

| Field | Meaning |
| --- | --- |
| CN | Common Name. This is commonly a hostname like www.server.com. |
| O | Organization |
| OU | Organizational Unit |
| L | Locality |
| S | State |
| C | Country |
| E | Email Address |

If a field value contains a comma, it must be quoted.

 **Encoded** *String*
*Default Value: ""*

The certificate (PEM/Base64 encoded). This field is used to assign a specific certificate. The [Store](#Certificate_f_Store) and [Subject](#Certificate_f_Subject) fields also may be used to specify a certificate.

When [Encoded](#Certificate_f_Encoded) is set, a search is initiated in the current [Store](#Certificate_f_Store) for the private key of the certificate. If the key is found, [Subject](#Certificate_f_Subject) is updated to reflect the full subject of the selected certificate; otherwise, [Subject](#Certificate_f_Subject) is set to an empty string.

 **EncodedB** *byte[]*
*Default Value: ""*

The certificate (PEM/Base64 encoded). This field is used to assign a specific certificate. The [Store](#Certificate_f_Store) and [Subject](#Certificate_f_Subject) fields also may be used to specify a certificate.

When [Encoded](#Certificate_f_Encoded) is set, a search is initiated in the current [Store](#Certificate_f_Store) for the private key of the certificate. If the key is found, [Subject](#Certificate_f_Subject) is updated to reflect the full subject of the selected certificate; otherwise, [Subject](#Certificate_f_Subject) is set to an empty string.

## Constructors

```text
public Certificate();
```

 Creates a instance whose properties can be set.

```text
public Certificate(String certificateFile);
```

 Opens * CertificateFile * and reads out the contents as an X.509 public key.

```text
public Certificate(byte[] encoded);
```

 Parses * Encoded * as an X.509 public key.

```text
public Certificate(int storeType, String store, String storePassword, String subject);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a file containing the certificate store. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the class will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(int storeType, String store, String storePassword, String subject, String configurationString);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a file containing the certificate store. * StorePassword * is the password used to protect the store.

 * ConfigurationString * is a newline-separated list of name-value pairs that may be used to modify the default behavior. Possible values include "PersistPFXKey", which shows whether or not the PFX key is persisted after performing operations with the private key. This correlates to the PKCS12_NO_PERSIST_KEY CryptoAPI option. The default value is True (the key is persisted). "Thumbprint" - an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load. When specified, this value is used to select the certificate in the store. This is applicable to the * cstUser * , * cstMachine * , * cstPublicKeyFile * , and * cstPFXFile * store types. "UseInternalSecurityAPI" shows whether the platform (default) or the internal security API is used when performing certificate-related operations.

 After the store has been successfully opened, the class will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(int storeType, String store, String storePassword, byte[] encoded);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a file containing the certificate store. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the class will load * Encoded * as an X.509 certificate and search the opened store for a corresponding private key.

```text
public Certificate(int storeType, byte[] store, String storePassword, String subject);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a byte array containing the certificate data. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the class will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(int storeType, byte[] store, String storePassword, String subject, String configurationString);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a byte array containing the certificate data. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the class will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(int storeType, byte[] store, String storePassword, byte[] encoded);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a byte array containing the certificate data. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the class will load * Encoded * as an X.509 certificate and search the opened store for a corresponding private key.

# SFTPConnection Type

A currently connected client.

## Remarks

This type describes the connection of a client that currently is connected to the class. You may use the different fields of this type to manage the connection.

The following fields are available:

- [Connected](#SFTPConnection_f_Connected)

- [ConnectionId](#SFTPConnection_f_ConnectionId)

- [ErrorMessage](#SFTPConnection_f_ErrorMessage)

- [FileData](#SFTPConnection_f_FileData)

- [LocalAddress](#SFTPConnection_f_LocalAddress)

- [ProtocolVersion](#SFTPConnection_f_ProtocolVersion)

- [RemoteHost](#SFTPConnection_f_RemoteHost)

- [RemotePort](#SFTPConnection_f_RemotePort)

- [Timeout](#SFTPConnection_f_Timeout)

## Fields

 **Connected** *boolean (read-only)*
*Default Value: False*

This field indicates the status of individual connections.

When *true*, the connection is established. Use the Disconnect method to disconnect an existing connection.

 **ConnectionId** *String (read-only)*
*Default Value: ""*

This field contains an Id generated by the class to identify each connection. This Id is unique to this connection.

 **ErrorMessage** *String*
*Default Value: ""*

[ErrorMessage](#SFTPConnection_f_ErrorMessage) is used together with status codes returned from events to send informative errors back to the secure file transfer protocol (SFTP) client through the SSH_FXP_STATUS message. If left blank, the class will set a default message based on the returned status code.

 **FileData** *String*
*Default Value: ""*

The [FileData](#SFTPConnection_f_FileData) should be set or read when processing read/write file events.

 **FileDataB** *byte[]*
*Default Value: ""*

The [FileData](#SFTPConnection_f_FileData) should be set or read when processing read/write file events.

 **LocalAddress** *String (read-only)*
*Default Value: ""*

This field shows the IP address of the interface through which the connection is passing.

[LocalAddress](#SFTPConnection_f_LocalAddress) is important for multihomed hosts in cases in which it can be used to identify the particular network interface an individual connection is going through.

 **ProtocolVersion** *int (read-only)*
*Default Value: 3*

The [ProtocolVersion](#SFTPConnection_f_ProtocolVersion) shows the secure file transfer protocol (SFTP) protocol version negotiated with the client when the SFTP connection was established.

 **RemoteHost** *String (read-only)*
*Default Value: ""*

The [RemoteHost](#SFTPConnection_f_RemoteHost) shows the IP address of the remote host through which the connection is coming.

The connection must be valid or an error will be fired.

If the class is configured to use a *SOCKS* firewall, the value assigned to this property may be preceded with an "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

 **RemotePort** *int (read-only)*
*Default Value: 0*

The [RemotePort](#SFTPConnection_f_RemotePort) shows the Transmission Control Protocol (TCP) port on the remote host through which the connection is coming.

The connection must be valid or an error will be fired.

 **Timeout** *int*
*Default Value: 0*

This field contains a timeout for the class.

If the [Timeout](#SFTPConnection_f_Timeout) field is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If [Timeout](#SFTPConnection_f_Timeout) is set to a positive value, the class will wait for the operation to complete before returning control.

The class will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not freeze and remains responsive.

If Timeout expires, and the operation is not yet complete, the class throws an exception.

NOTE: By default, all timeouts are *inactivity timeouts*, that is, the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for [Timeout](#SFTPConnection_f_Timeout) is specified by the DefaultTimeout property.

## Constructors

```text
public SFTPConnection();
```

# SSHPrompt Type

A prompt to provide to the client during keyboard-interactive authentication.

## Remarks

This type describes a prompt the Secure Shell (SSH) daemon will send to the client when requesting keyboard-interactive authentication.

The following fields are available:

- [Echo](#SSHPrompt_f_Echo)

- [Prompt](#SSHPrompt_f_Prompt)

## Fields

 **Echo** *boolean*
*Default Value: False*

This field specifies whether or not the client should echo the value entered by the user.

 **Prompt** *String*
*Default Value: ""*

This field contains the prompt label or text the client should present to the user.

## Constructors

```text
public SSHPrompt();
```

```text
public SSHPrompt(String prompt, boolean echo);
```

# Config Settings ([SFTPServer](#sftpserver-class) Class)

 The class accepts one or more of the following *configuration settings*. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these *internal properties* is provided through the [Config](#config-method-sftpserver-class) method.

### SFTPServer Config Settings

**DirListBufferSize[ConnectionId]**: The number of entries to be returned in one response to a request for a directory listing.The default value for this configuration setting is 1, which means that the class will return one entry at a time in response to a request for a directory listing. Changing this value will allow the class to bundle multiple entries into a single response.

**MaskSensitiveData**: Masks passwords in logs.The default value is True. When set to True, the class will mask passwords that otherwise would appear in its logs.

**MaxStartupsConnections**: The number of unauthenticated connections that the server will accept. This configuration setting specifies the number of unauthenticated connections the server will accept before rejecting new connection attempts. The default value is 50. Additionally, unauthenticated connections may only request a buffer of 256 KB and will be disconnected if they are not authenticated within 120 seconds.

**ProtocolVersion**: The highest allowable SFTP version to use.This configuration setting governs the highest allowable secure file transfer protocol (SFTP) version to use when negotiating the version with the client. The default value is 3 because this is the most common version. The class supports values from 3 to 6.

**RestrictUserToHomeDir[ConnectionId]**: Whether to restrict the user to their home directory.When True, this configuration setting will restrict the user to the path specified by the "HomeDir" parameter in the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event. When False (default), the user will be able to navigate outside of the home directory. "ConnectionId" specifies the connection to which the restriction applies.

```text
sftpserver.Config("RestrictUserToHomeDir[" + e.ConnectionId + "]=true");
```

## Example

If the [RootDirectory](#rootdirectory-property-sftpserver-class) property of a certain SFTP server is set to */*, then the directory structure of the server might look like this:

```text
Root Directory: /

bin
boot
etc
home
  user1
    testfolder
```

 When RestrictUserToHomeDir is set to True and the "HomeDir" parameter is set to */home/user1*, User 1 will land in the home directory and see the following file system when it connects:

```text
Home Directory: /home/user1

/testfolder
```

 The client will be able to perform operations only against */home/user1* and its children, but the client can see its working directory relative to the server root directory.

**ServerEOL**: Specifies the line endings used in files on the server.This configuration setting is used to inform the connecting client what line endings are used in the files on the system. This is applicable only when [ProtocolVersion](#ProtocolVersion) is set to 4 or higher and a connecting client negotiates protocol version 4 or higher. When a client negotiates version 4 or higher, this value is reported using the "newline" protocol convention. The client may use that to transform line endings when downloading. The default value is CrLF.

**SFTPErrorMessage[ConnectionId]**: Specifies the error message to be returned to the client.If an SFTP operation would return an error to the client (e.g., permission denied, file does not exist), then this configuration setting can be used to specify the error message to be returned to the client. This optional configuration setting is effective only when set within an event that uses the "StatusCode" field.

**UnixStyleDateFormat**: Controls whether to use the Unix-style date format in directory listings.When set to True, the class will report entries in the Unix-style date format: if the modification time is within the previous 180 days, the date will be formatted as "Mmm dd hh:mm"; otherwise, it will be formatted as "Mmm dd yyyy".

**UserRootDirectory[ConnectionId]**: The path of the server root directory for a particular user.When set to a subdirectory of the server root, this configuration setting will override the server [RootDirectory](#rootdirectory-property-sftpserver-class) for a particular user. The "HomeDir" parameter of the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event will represent the initial path of the client relative to the UserRootDirectory. "ConnectionId" specifies the connection to which the restriction applies.

```text
sftpserver.Config("UserRootDirectory[" + e.ConnectionId + "]=" + userRootDirectory );
```

## Example

If the [RootDirectory](#rootdirectory-property-sftpserver-class) property of a certain SFTP server is set to */*, then the directory structure of the server might look like this:

```text
Root Directory: /

bin
boot
etc
home
  user1
    testfolder
```

 When UserRootDirectory is set to */home/user1* and the HomeDir event parameter is set to */*, when User 1 connects they will land in the home directory and see the following file system:

```text
Home Directory: /

/testfolder
```

 The client will be able to perform operations only against */* and its children, and the client cannot see its working directory relative to the server root directory.

### SSHServer Config Settings

**AltSSHCertCount**: The number of records in the AltSSHCert configuration settings.This configuration setting controls the size of the following arrays:

- [AltSSHCertStore](#AltSSHCertStore)
- [AltSSHCertStorePassword](#AltSSHCertStorePassword)
- [AltSSHCertStoreType](#AltSSHCertStoreType)
- [AltSSHCertSubject](#AltSSHCertSubject)

The array indices start at *0* and end at *AltSSHCertCount - 1*.

The AltSSHCert configuration settings are used to specify alternative digital certificates to the one set using the [SSHCert](#sshcert-property-sftpserver-class). The server will determine the certificate to use during Secure Shell (SSH) negotiation based on the public key algorithm requested by the connecting client. A certificate with a private key is required for session authentication and encryption. The [AltSSHCertSubject](#AltSSHCertSubject) setting must be set last. When [AltSSHCertSubject](#AltSSHCertSubject) is set, a search is initiated in the [AltSSHCertStore](#AltSSHCertStore) and the certificate is loaded.

The alternative server certificate specified by these settings must be configured before setting [Listening](#listening-property-sftpserver-class) to *true*. For example:

```csharp
sftpserver.Config("AltSSHCertCount =1");
sftpserver.Config("AltSSHCertStoreType[0]=7");           //PEM Key Blob
sftpserver.Config("AltSSHCertStore[0]=" + ed25519Key);   //PEM formatted string
sftpserver.Config("AltSSHCertSubject[0]=*");             //Load the first (and only) certificate
```

**AltSSHCertStore[i]**: The name of the certificate store.The name of the certificate store. This configuration setting is used when specifying an alternative [SSHCert](#sshcert-property-sftpserver-class).

The [AltSSHCertStoreType](#AltSSHCertStoreType) specifies the type of the certificate store specified by [AltSSHCertStore](#AltSSHCertStore). If the store is password protected, specify the password in the [AltSSHCertStorePassword](#AltSSHCertStorePassword).

[AltSSHCertStore](#AltSSHCertStore) is used in conjunction with the [AltSSHCertSubject](#AltSSHCertSubject) field to specify the certificate.

 Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

|  |  |
| --- | --- |
| MY | A certificate store holding personal certificates with their associated private keys. |
| CA | Certifying authority certificates. |
| ROOT | Root certificates. |

In Java, the certificate store normally is a file containing certificates and optional private keys.

When the certificate store type is *cstPFXFile*, this property must be set to the name of the file. When the type is *cstPFXBlob*, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

**AltSSHCertStorePassword[i]**: The password used to open the certificate store.If the certificate store requires a password, this configuration setting can be used to specify that password. This setting is used when specifying an alternative [SSHCert](#sshcert-property-sftpserver-class)

**AltSSHCertStoreType[i]**: The type of certificate store.This configuration setting specifies the type of certificate store. This setting is used when specifying an alternate [SSHCert](#sshcert-property-sftpserver-class). Possible values are as follows:

|  |  |
| --- | --- |
| 0 | User - This is the default for Windows. This specifies that the certificate store is a certificate store owned by the current user. NOTE: This store type is not available in Java. |
| 1 | Machine - For Windows, this specifies that the certificate store is a machine store. NOTE: This store type is not available in Java. |
| 2 | PFXFile - The certificate store is the name of a PFX (PKCS12) file containing certificates. |
| 3 | PFXBlob - The certificate store is a string (binary or Base64-encoded) representing a certificate store in PFX (PKCS12) format. |
| 4 | JKSFile - The certificate store is the name of a Java Key Store (JKS) file containing certificates. NOTE: This store type is available only in Java. |
| 5 | JKSBlob - The certificate store is a string (binary or Base64-encoded) representing a certificate store in Java Key Store (JKS) format. NOTE: This store type is available only in Java. |
| 6 | PEMKeyFile - The certificate store is the name of a PEM-encoded file that contains a private key and an optional certificate. |
| 7 | PEMKeyBlob - The certificate store is a string (binary or Base64-encoded) that contains a private key and an optional certificate. |
| 14 | PPKFile - The certificate store is the name of a file that contains a PPK (PuTTY Private Key). |
| 15 | PPKBlob - The certificate store is a string (binary) that contains a PPK (PuTTY Private Key). |
| 16 | XMLFile - The certificate store is the name of a file that contains a certificate in XML format. |
| 17 | XMLBlob - The certificate store is a string that contains a certificate in XML format. |

**AltSSHCertSubject[i]**: The alternative certificate subject.The subject of the certificate. This configuration setting is used when specifying an alternative [SSHCert](#sshcert-property-sftpserver-class). The special value of *** may be used to select the first certificate in the store.

**ClientSSHVersionString[ConnectionId]**: The client's version string.This configuration setting returns a connected client's SSH version string. It may be queried inside [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class).

```csharp
sftpserver1.OnSSHUserAuthRequest += (obj, ev) =>
{
  Console.WriteLine(sftpserver1.Config("ClientSSHVersionString[" + ev.ConnectionId + "]"));
};
```

**FireAuthRequestAfterSig**: Whether to fire an informational event after the public key signature has been verified.When performing public key authentication, the connecting client will present both the public key as well as a signature to verify ownership of the corresponding private key. The class will automatically verify the signature and respond to the client to indicate whether the signature could be verified and the connection can continue. This configuration setting controls whether an additional informational event fires to report the result of the signature verification.

If set to *true*, the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event will fire twice per public key authentication attempt. The first time the event fires for public key authentication as usual. After verification of the signature has taken place, the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) will fire again, and the *AuthMethod* parameter will contain the string *sigstatus*. The *AuthParam* parameter will contain a value of *0* (invalid signature) or *1* (valid signature). If the signature is invalid, it will always result in a rejected authentication attempt.

**KeyboardInteractivePrompts[ConnectionId]**: Specifies custom keyboard-interactive prompts for particular connections.By default, setting the [KeyboardInteractivePrompts](#keyboardinteractiveprompts-property-sftpserver-class) property will cause those prompts to be used for every user attempting to connect. This setting can be used to override the [KeyboardInteractivePrompts](#keyboardinteractiveprompts-property-sftpserver-class) property and provide unique prompts for certain connections.

This configuration setting takes a list of prompts to display to the client, and each prompt includes an 'echo' parameter to specify whether or not to echo the client's response to the prompt. The prompt and the echo parameter should be separated by a comma (","), and each prompt should be separated by a semicolon (";"). For example:

"KeyboardInteractivePrompts[connId]=First prompt,echo=false;Second prompt,echo=true"

This configuration setting can be set anywhere in code, but it is necessary to know the ConnectionId for the specific connection beforehand; as such, it is generally recommended to set this configuration inside the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event. Because connecting clients initially attempt to connect with and *AuthMethod* of 'none' (with the understanding that this attempt will fail, and the SSH server will advertise which authentication methods it supports), it is recommended to check the *AuthMethod*, *User*, and *ConnectionId* parameters of the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event and set this configuration setting accordingly.

When SSHServer displays keyboard-interactive prompts, it will first check to see if this configuration setting is populated for the current ConnectionId. If it is, the prompts set here will be used instead of those set in the [KeyboardInteractivePrompts](#keyboardinteractiveprompts-property-sftpserver-class) property. Otherwise, the [KeyboardInteractivePrompts](#keyboardinteractiveprompts-property-sftpserver-class) property will function as normal.

**KeyRenegotiationThreshold**: Sets the threshold for the SSH Key Renegotiation.This property allows you to specify the threshold, in the number of bytes, for the Secure Shell (SSH) key renegotiation. The default value for this property is set to 1 GB.

**Example. Setting the Threshold to 500 MB:**

```text
SSHComponent.Config("KeyRenegotiationThreshold=524288000")
```

**LogLevel**: Specifies the level of detail that is logged.This configuration setting controls the level of detail that is logged through the [Log](#log-event-sftpserver-class) event. Possible values are as follows:

|  |  |
| --- | --- |
| 0 (None) | No messages are logged. |
| 1 (Info - Default) | Informational events such as Secure Shell (SSH) handshake messages are logged. |
| 2 (Verbose) | Detailed data such as individual packet information are logged. |
| 3 (Debug) | Debug data including all relevant sent and received bytes are logged. |

**MaxAuthAttempts**: The maximum authentication attempts allowed before forcing a disconnect.This configuration setting specifies the maximum amount of authentication attempts that will be allowed before forcibly disconnecting the client.

**NegotiatedStrictKex[ConnectionId]**: Returns whether strict key exchange was negotiated to be used.Returns whether strict key exchange (strict kex) was negotiated during the SSH handshake. This is a per-connection configuration setting accessed by passing the ConnectionId. If strict kex is being used, then this will return *"True"*. If strict kex is not being used, then this will return *"False"*.

```text
component.Config("NegotiatedStrictKex[connId]")
```

**ServerSSHVersionString**: The SSH version string sent to connecting clients.This configuration setting specifies the version string value that is sent to all connecting clients. This may be set to specify server specific information. The default value is "SSH-2.0-IPWorks SSH Daemon 2024". When setting your own value, it must begin with "SSH-2.0-" because this is a standard format that specifies the supported SSH version.

**SSHKeepAliveCountMax**: The maximum number of keep alive packets to send without a response.This configuration setting specifies the maximum number of keep-alive packets to send when no response is received. Normally a response to a keep-alive packet is received right away. If no response is received, the class will continue to send keep-alive packets until [SSHKeepAliveCountMax](#SSHKeepAliveCountMax) is reached. If this is reached, the class will assume the connection is broken and disconnect. The default value is 5.

**SSHKeepAliveInterval**: The interval between keep alive packets.This configuration setting specifies the number of seconds between keep-alive packets. If set to a positive value, the class will send a SSH keep-alive packet after [KeepAliveInterval](#KeepAliveInterval) seconds of inactivity. This configuration setting takes effect only when there is no activity. If any data are sent or received over the connection, it will reset the timer.

The default value is *0*, meaning no keep alives will be sent.

NOTE: The SSHREVERSETUNNEL class uses a default value of 30.

**SSHKeyExchangeAlgorithms**: Specifies the supported key exchange algorithms.This configuration setting may be used to specify the list of supported key exchange algorithms used during Secure Shell (SSH) negotiation. The value should contain a comma-separated list of algorithms. Supported algorithms are as follows:

- curve25519-sha256
- curve25519-sha256@libssh.org
- diffie-hellman-group1-sha1
- diffie-hellman-group14-sha1
- diffie-hellman-group14-sha256
- diffie-hellman-group16-sha512
- diffie-hellman-group18-sha512
- diffie-hellman-group-exchange-sha256
- diffie-hellman-group-exchange-sha1
- ecdh-sha2-nistp256
- ecdh-sha2-nistp384
- ecdh-sha2-nistp521
- gss-group14-sha256
- gss-group16-sha512
- gss-nistp256-sha256
- gss-curve25519-sha256
- gss-group14-sha1
- gss-gex-sha1
- mlkem768x25519-sha256

 The default value is *curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,mlkem768x25519-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1,gss-group14-sha256,gss-group16-sha512,gss-nistp256-sha256,gss-curve25519-sha256,gss-group14-sha1,gss-gex-sha1*.

**SSHMacAlgorithms**: Specifies the supported Mac algorithms.This configuration setting may be used to specify an alternate list of supported Mac algorithms used during SSH negotiation. This also specifies the order in which the Mac algorithms are preferred. The value should contain a comma-separated list of algorithms. Supported algorithms are as follows:

- hmac-sha1
- hmac-md5
- hmac-sha1-96
- hmac-md5-96
- hmac-sha2-256
- hmac-sha2-256-96
- hmac-sha2-512
- hmac-sha2-512-96
- hmac-ripemd160
- hmac-ripemd160-96
- hmac-sha2-256-etm@openssh.com
- hmac-sha2-512-etm@openssh.com
- hmac-sha2-256-96-etm@openssh.com
- hmac-sha2-512-96-etm@openssh.com
- umac-64@openssh.com
- umac-64-etm@openssh.com
- umac-128@openssh.com
- umac-128-etm@openssh.com

 The default value is *hmac-sha2-256,hmac-sha2-512,hmac-sha1,hmac-md5,hmac-ripemd160,hmac-sha1-96,hmac-md5-96,hmac-sha2-256-96,hmac-sha2-512-96,hmac-ripemd160-96,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-64@openssh.com,umac-64-etm@openssh.com,umac-128@openssh.com,umac-128-etm@openssh.com*.

**SSHPubKeyAuthSigAlgorithms**: Specifies the allowed signature algorithms used by a client performing public key authentication.This configuration setting specifies a list of signature algorithms that a client is allowed to use when authenticating to the server using public key authentication. This applies only when public key authentication is performed by the client.

The configuration setting should be a comma-separated list of algorithms. When a client connects, the server will verify that the client performing the public key authentication has used one of the specified signature algorithms. If the client uses a signature algorithm that is not in the list, the connection will be rejected.

Possible values areas follows:

- ssh-rsa
- rsa-sha2-256
- rsa-sha2-512
- ssh-dss
- ecdsa-sha2-nistp256
- ecdsa-sha2-nistp384
- ecdsa-sha2-nistp521
- ssh-ed25519
- x509v3-sign-rsa
- x509v3-sign-dss

The default value in Windows is *ssh-rsa,rsa-sha2-256,rsa-sha2-512,x509v3-sign-rsa,ssh-dss,x509v3-sign-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519*.

**SSHPublicKeyAlgorithms**: Specifies the supported public key algorithms for the server's public key. This configuration setting specifies the allowed public key algorithms for the server's public key. This list controls only the public key algorithm used when authenticating the server's public key. This list has no bearing on the public key algorithms that can be used by the client when performing public key authentication to the server. The default value is *ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-256,rsa-sha2-512,ssh-rsa,ssh-dss,x509v3-sign-rsa,x509v3-sign-dss*.

**SSHVersionPattern**: The pattern used to match the remote host's version string.This configuration setting specifies the pattern used to accept or deny the remote host's SSH version string. It takes a comma-delimited list of patterns to match. The default value is "*SSH-1.99-*,*SSH-2.0-*" and will accept connections from SSH 1.99 and 2.0 hosts. As an example, the following value would accept connections for SSH 1.99, 2.0, and 2.99 hosts:

```text
*SSH-1.99-*,*SSH-2.0-*,*SSH-2.99-*
```

**UserAuthBanner[ConnectionId]**: A custom user authentication banner.This configuration setting specifies a custom user authentication banner, which may be sent to give the client more information regarding an authentication attempt. "ConnectionId" specifies the particular connection to send the message to. This configuration option is effective only when set within the [SSHUserAuthRequest](#sshuserauthrequest-event-sftpserver-class) event.

**UseStrictKeyExchange**: Specifies how strict key exchange is supported.This configuration setting controls whether strict key exchange (strict kex) is enabled to mitigate the Terrapin attack. When enabled, the class will indicate support for strict key exchange by automatically including the pseudo-algorithm *kex-strict-c-v00@openssh.com* for client classes and *kex-strict-s-v00@openssh.com* for server classes in the list of supported key exchange algorithms.

Because both client and server must implement strict key exchange to effectively mitigate the Terrapin attack, the class provides options to further control the behavior in different scenarios. Possible values for this setting are as follows:

|  |  |
| --- | --- |
| 0 | Disabled. Strict key exchange is not supported in the class. |
| 1 (default) | Enabled, but not enforced. This setting enables strict key exchange, but if the remote host does not support strict key exchange the connection is still allowed to continue. |
| 2 | Enabled, but will reject affected algorithms if the remote host does not support strict key exchange. If the remote host supports strict key exchange, all algorithms may be used. If the remote host does not support strict key exchange, the connection will continue only if the selected encryption and message authentication code (MAC) algorithms are not affected by the Terrapin attack. |
| 3 | Required. If the remote host does not support strict key exchange, the connection will fail. |

### TCPServer Config Settings

**AllowedClients**: A comma-separated list of host names or IP addresses that can access the class.This configuration setting defines a comma-separated list of host names or IPv4 addresses that may access the class. The wildcard character "*" is supported. The default value is "*" and all connections are accepted.

When a client connects, the client's address is checked against the list defined here. If there is no match, the [ConnectionRequest](#connectionrequest-event-sftpserver-class) event fires with an *Accept* value set to *false*. If no action is taken within the [ConnectionRequest](#connectionrequest-event-sftpserver-class) event, the client will be disconnected.

**BindExclusively**: Whether or not the component considers a local port reserved for exclusive use.If this is *true* (default), the component will bind to the local port with the ExclusiveAddressUse option set, meaning that nothing else can bind to the same port. Also the component will not be able to bind to local ports that are already in use by some other instance, and attempts to do so will result in failure.

**BlockedClients**: A comma-separated list of host names or IP addresses that cannot access the class.This configuration setting defines a comma-separated list of host names or IPv4 addresses that cannot access the class.The default value is "" and all connections are accepted.

When a client connects, the client's address is checked against the list defined here. If there is a match, the [ConnectionRequest](#connectionrequest-event-sftpserver-class) event fires with an *Accept* value set to *false*. If no action is taken within the [ConnectionRequest](#connectionrequest-event-sftpserver-class) event, the client will not be connected.

**CloseStreamAfterTransfer**: If true, the component will close the upload or download stream after the transfer.This configuration setting determines whether the input or output stream is closed after the transfer completes. When set to True (default), all streams will be closed after a transfer is completed. To keep streams open after the transfer of data, set this to False. The default value is True.

**DefaultConnectionTimeout**: The inactivity timeout applied to the SSL handshake.This configuration setting specifies the inactivity (in seconds) to apply to incoming Secure Sockets Layer (SSL) connections. When set to a positive value, if the other end is unresponsive for the specified number of seconds, the connection will timeout. This is not applicable to the entire handshake. It is applicable only to the inactivity of the connecting client during the handshake if a response is expected and none is received within the timeout window. The default value is 0, and no connection-specific timeout is applied.

NOTE: This is applicable only to incoming SSL connections. This should be set only if there is a specific reason to do so.

**InBufferSize**: The size in bytes of the incoming queue of the socket. This is the size of an internal queue in the Transmission Control Protocol (TCP)/IP stack. You can increase or decrease its size depending on the amount of data that you will be receiving. Increasing the value of the [InBufferSize](#InBufferSize) setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated, the [InBufferSize](#InBufferSize) reverts to its defined size. The same thing will happen if you attempt to make it too large or too small.

[InBufferSize](#InBufferSize) is shared among incoming connections. When the setting is set, the corresponding value is set for incoming connections as they are accepted. Existing connections are not modified.

**KeepAliveInterval**: The retry interval, in milliseconds, to be used when a TCP keep-alive packet is sent and no response is received.A TCP keep-alive packet will be sent after a period of inactivity, as defined by [KeepAliveTime](#KeepAliveTime). If no acknowledgment is received from the remote host, the keep-alive packet will be sent again. This setting specifies the interval at which the successive keep-alive packets are sent in milliseconds. If this value is not specified here, the system default is 1 second. This setting is applicable to all connections.

NOTE: This value is not applicable in macOS.

**KeepAliveTime**: The inactivity time in milliseconds before a TCP keep-alive packet is sent.By default, the operating system will determine the time a connection is idle before a TCP keep-alive packet is sent. If this value is not specified here, the system default is 2 hours. In many cases, a shorter interval is more useful. Set this value to the desired interval in milliseconds. This setting is applicable to all connections.

**MaxConnections**: The maximum number of connections available. This is the maximum number of connections available. This setting must be set before [Listening](#listening-property-sftpserver-class) is set to *true*, and once set, it can no longer be changed for the current instance of the class. The maximum value for this setting is 100,000 connections. Use this setting with caution. Extremely large values may affect performance.

**OutBufferSize**: The size in bytes of the outgoing queue of the socket.This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be sending. Increasing the value of the [OutBufferSize](#OutBufferSize) setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated the [OutBufferSize](#OutBufferSize) reverts to its defined size. The same thing will happen if you attempt to make it too large or too small.

[OutBufferSize](#OutBufferSize) is shared among incoming connections. When the setting is set, the corresponding value is set for incoming connections as they are accepted. Existing connections are not modified.

**PreferredDHGroupBits**: Size of the Diffie-Hellman group, in bits.This configuration setting specifies the key length used by the Diffie-Hellman key algorithm. The default value is *2048* (bits).

**TcpNoDelay**: Whether or not to delay when sending packets. When set to True, the socket will send all data that are ready to send at once. When set to False, the socket will send smaller buffered packets of data at small intervals. This is known as the Nagle algorithm.

By default, this configuration setting is set to False.

**UseIPv6**: Whether to use IPv6.When set to 0 (default), the class will use IPv4 exclusively. When set to 1, the class will use IPv6 exclusively. When set to 2, the class will listen for both IPv4 and IPv6 connections. If IPv6 is not available on the system, only IPv4 will be used. The default value is 0. Possible values are as follows:

|  |  |
| --- | --- |
| 0 | IPv4 Only |
| 1 | IPv6 Only |
| 2 | IPv6 and IPv4 |

### SSL Config Settings

**LogSSLPackets**: Controls whether SSL packets are logged when using the internal security API.When SSLProvider is set to *Internal*, this configuration setting controls whether Secure Sockets Layer (SSL) packets should be logged. By default, this configuration setting is *False*, as it is useful only for debugging purposes.

When enabled, SSL packet logs are output using the SSLStatus event, which will fire each time an SSL packet is sent or received.

Enabling this configuration setting has no effect if SSLProvider is set to *Platform*.

**ReuseSSLSession**: Determines if the SSL session is reused.

If set to True, the class will reuse the context if and only if the following criteria are met:

- The target host name is the same.
- The system cache entry has not expired (default timeout is 10 hours).
- The application process that calls the function is the same.
- The logon session is the same.
- The instance of the class is the same.

**SSLCACerts**: A newline separated list of CA certificates to be included when performing an SSL handshake.When SSLProvider is set to *Internal*, this configuration setting specifies one or more CA certificates to be included with the SSLCert property. Some servers or clients require the entire chain, including CA certificates, to be presented when performing SSL authentication. The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

```text
-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----
```

**SSLCheckCRL**: Whether to check the Certificate Revocation List for the server certificate.This configuration setting specifies whether the class will check the Certificate Revocation List (CRL) specified by the server certificate. If set to 1 or 2, the class will first obtain the list of CRL URLs from the server certificate's CRL distribution points extension. The class will then make HTTP requests to each CRL endpoint to check the validity of the server's certificate. If the certificate has been revoked or any other issues are found during validation the class throws an exception.

When set to 0 (default), the CRL check will not be performed by the class. When set to 1, it will attempt to perform the CRL check, but it will continue without an error if the server's certificate does not support CRL. When set to 2, it will perform the CRL check and will throw an error if CRL is not supported.

This configuration setting is supported only in the Java, C#, and C++ editions. In the C++ edition, it is supported only on Windows operating systems.

**SSLCheckOCSP**: Whether to use OCSP to check the status of the server certificate.This configuration setting specifies whether the class will use OCSP to check the validity of the server certificate. If set to 1 or 2, the class will first obtain the Online Certificate Status Protocol (OCSP) URL from the server certificate's OCSP extension. The class will then locate the issuing certificate and make an HTTP request to the OCSP endpoint to check the validity of the server's certificate. If the certificate has been revoked or any other issues are found during validation, the class throws an exception.

When set to 0 (default), the class will not perform an OCSP check. When set to 1, it will attempt to perform the OCSP check, but it will continue without an error if the server's certificate does not support OCSP. When set to 2, it will perform the OCSP check and will throw an error if OCSP is not supported.

This configuration setting is supported only in the Java, C#, and C++ editions. In the C++ edition, it is supported only on Windows operating systems.

**SSLCipherStrength**: The minimum cipher strength used for bulk encryption. This minimum cipher strength is largely dependent on the security modules installed on the system. If the cipher strength specified is not supported, an error will be returned when connections are initiated.

NOTE: This configuration setting contains the minimum cipher strength requested from the security library. The actual cipher strength used for the connection is shown by the SSLStatus event.

Use this configuration setting with caution. Requesting a lower cipher strength than necessary could potentially cause serious security vulnerabilities in your application.

When the provider is OpenSSL, [SSLCipherStrength](#SSLCipherStrength) is currently not supported. This functionality is instead made available through the [OpenSSLCipherList](#OpenSSLCipherList) configuration setting.

**SSLClientCACerts**: A newline separated list of CA certificates to use during SSL client certificate validation.This configuration setting is only applicable to server components (e.g., TCPServer) see [SSLServerCACerts](#SSLServerCACerts) for client components (e.g., TCPClient). This setting can be used to optionally specify one or more CA certificates to be used when verifying the client certificate that is presented by the client during the SSL handshake when SSLAuthenticateClients is enabled. When verifying the client's certificate, the certificates trusted by the system will be used as part of the verification process. If the client's CA certificates are not installed to the trusted system store, they may be specified here so they are included when performing the verification process. This configuration setting should be set only if the client's CA certificates are not already trusted on the system and cannot be installed to the trusted system store.

The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

```text
-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----
```

**SSLContextProtocol**: The protocol used when getting an SSLContext instance.Possible values are SSL, SSLv2, SSLv3, TLS, and TLSv1. Use this configuration setting only in case your security provider does not support TLS. This is the parameter "protocol" inside the SSLContext.getInstance(protocol) call.

**SSLEnabledCipherSuites**: The cipher suite to be used in an SSL negotiation.This configuration setting enables the cipher suites to be used in SSL negotiation.

By default, the enabled cipher suites will include all available ciphers ("*").

The special value "*" means that the class will pick all of the supported cipher suites. If [SSLEnabledCipherSuites](#SSLEnabledCipherSuites) is set to any other value, only the specified cipher suites will be considered.

Multiple cipher suites are separated by semicolons.

NOTE: This value must be set after SSLProvider is set.

Example values:

```text
obj.config("SSLEnabledCipherSuites=*");
obj.config("SSLEnabledCipherSuites=SSL_RSA_WITH_RC4_128_SHA");
obj.config("SSLEnabledCipherSuites=SSL_RSA_WITH_RC4_128_SHA; SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA");
```

 Possible values when SSLProvider is set to *Platform* include the following:

- SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
- SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA
- SSL_RSA_WITH_RC4_128_SHA
- SSL_RSA_WITH_DES_CBC_SHA
- SSL_RSA_EXPORT_WITH_DES40_CBC_SHA
- SSL_DH_anon_WITH_DES_CBC_SHA
- SSL_RSA_EXPORT_WITH_RC4_40_MD5
- SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA
- SSL_DH_anon_EXPORT_WITH_RC4_40_MD5
- SSL_DHE_DSS_WITH_DES_CBC_SHA
- SSL_RSA_WITH_NULL_MD5
- SSL_DH_anon_WITH_3DES_EDE_CBC_SHA
- SSL_DHE_RSA_WITH_DES_CBC_SHA
- SSL_DH_anon_EXPORT_WITH_DES40_CBC_SHA
- SSL_RSA_WITH_NULL_SHA
- SSL_DH_anon_WITH_RC4_128_MD5
- SSL_RSA_WITH_RC4_128_MD5
- SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA
- SSL_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDH_ECDSA_WITH_NULL_SHA
- TLS_DH_anon_WITH_AES_128_CBC_SHA256 (Not Recommended)
- TLS_ECDH_anon_WITH_RC4_128_SHA
- TLS_DH_anon_WITH_AES_128_CBC_SHA (Not Recommended)
- TLS_DHE_RSA_WITH_AES_128_CBC_SHA
- TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA
- TLS_KRB5_WITH_3DES_EDE_CBC_SHA
- TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
- TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA
- TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
- TLS_KRB5_EXPORT_WITH_RC4_40_SHA
- TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256
- TLS_ECDHE_RSA_WITH_RC4_128_SHA
- TLS_ECDH_ECDSA_WITH_RC4_128_SHA
- TLS_ECDH_anon_WITH_NULL_SHA
- TLS_ECDHE_ECDSA_WITH_RC4_128_SHA
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
- TLS_RSA_WITH_NULL_SHA256
- TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA
- TLS_KRB5_WITH_RC4_128_MD5
- TLS_ECDHE_ECDSA_WITH_NULL_SHA
- TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDH_RSA_WITH_RC4_128_SHA
- TLS_EMPTY_RENEGOTIATION_INFO_SCSV
- TLS_KRB5_WITH_3DES_EDE_CBC_MD5
- TLS_KRB5_WITH_RC4_128_SHA
- TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDH_RSA_WITH_NULL_SHA
- TLS_ECDH_RSA_WITH_AES_128_CBC_SHA
- TLS_KRB5_WITH_DES_CBC_MD5
- TLS_KRB5_EXPORT_WITH_RC4_40_MD5
- TLS_KRB5_EXPORT_WITH_DES_CBC_40_MD5
- TLS_ECDH_anon_WITH_AES_128_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
- TLS_KRB5_WITH_DES_CBC_SHA
- TLS_RSA_WITH_AES_128_CBC_SHA
- TLS_KRB5_EXPORT_WITH_DES_CBC_40_SHA
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
- TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256
- TLS_ECDHE_RSA_WITH_NULL_SHA
- TLS_RSA_WITH_AES_128_CBC_SHA256
- TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_DHE_DSS_WITH_AES_128_CBC_SHA

Possible values when SSLProvider is set to *Internal* include the following:

- TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
- TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384
- TLS_RSA_WITH_AES_256_GCM_SHA384
- TLS_RSA_WITH_AES_128_GCM_SHA256
- TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256
- TLS_DHE_DSS_WITH_AES_256_GCM_SHA384
- TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256
- TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
- TLS_DHE_DSS_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
- TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384
- TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
- TLS_RSA_WITH_AES_256_CBC_SHA256
- TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
- TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384
- TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
- TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
- TLS_RSA_WITH_AES_128_CBC_SHA256
- TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256
- TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256
- TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
- TLS_RSA_WITH_AES_256_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
- TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
- TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA
- TLS_DHE_RSA_WITH_AES_256_CBC_SHA
- TLS_ECDH_RSA_WITH_AES_256_CBC_SHA
- TLS_DHE_DSS_WITH_AES_256_CBC_SHA
- TLS_RSA_WITH_AES_128_CBC_SHA
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
- TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA
- TLS_ECDH_RSA_WITH_AES_128_CBC_SHA
- TLS_DHE_RSA_WITH_AES_128_CBC_SHA
- TLS_DHE_DSS_WITH_AES_128_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
- TLS_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_RSA_WITH_DES_CBC_SHA
- TLS_DHE_RSA_WITH_DES_CBC_SHA
- TLS_DHE_DSS_WITH_DES_CBC_SHA
- TLS_RSA_WITH_RC4_128_MD5
- TLS_RSA_WITH_RC4_128_SHA

When TLS 1.3 is negotiated (see [SSLEnabledProtocols](#SSLEnabledProtocols)), only the following cipher suites are supported:

- TLS_AES_256_GCM_SHA384
- TLS_CHACHA20_POLY1305_SHA256
- TLS_AES_128_GCM_SHA256

[SSLEnabledCipherSuites](#SSLEnabledCipherSuites) is used together with [SSLCipherStrength](#SSLCipherStrength).

**SSLEnabledProtocols**: Used to enable/disable the supported security protocols.This configuration setting is used to enable or disable the supported security protocols.

Not all supported protocols are enabled by default. The default value is *4032* for client components, and *3072* for server components. To specify a combination of enabled protocol versions set this config to the binary *OR* of one or more of the following values:

|  |  |
| --- | --- |
| TLS1.3 | 12288 (Hex 3000) |
| TLS1.2 | 3072 (Hex C00) (Default - Client and Server) |
| TLS1.1 | 768 (Hex 300) (Default - Client) |
| TLS1 | 192 (Hex C0) (Default - Client) |
| SSL3 | 48 (Hex 30) |
| SSL2 | 12 (Hex 0C) |

Note that only TLS 1.2 is enabled for server components that accept incoming connections. This adheres to industry standards to ensure a secure connection. Client components enable TLS 1.0, TLS 1.1, and TLS 1.2 by default and will negotiate the highest mutually supported version when connecting to a server, which should be TLS 1.2 in most cases.

**SSLEnabledProtocols: Transport Layer Security (TLS) 1.3 Notes:**

By default when TLS 1.3 is enabled, the class will first try to use the platform TLS 1.3 implementation when the SSLProvider is set to Automatic for all editions. If the platform TLS 1.3 implementation is not available, the internal implementation will be used.

In editions that are designed to run on Windows, SSLProvider can be set to Platform to use the platform implementation instead of the internal implementation. When configured in this manner, please note that the platform provider is supported only on Windows 11/Windows Server 2022 and up. The default internal provider is available on all platforms and is not restricted to any specific OS version.

If set to *1* (Platform provider), please be aware of the following notes:

- The platform provider is available only on Windows 11/Windows Server 2022 and up.
- [SSLEnabledCipherSuites](#SSLEnabledCipherSuites) and other similar SSL configuration settings are not supported.
- If [SSLEnabledProtocols](#SSLEnabledProtocols) includes both TLS 1.3 and TLS 1.2, these restrictions are still applicable even if TLS 1.2 is negotiated. Enabling TLS 1.3 with the platform provider changes the implementation used for all TLS versions.

**SSLEnabledProtocols: SSL2 and SSL3 Notes: **

SSL 2.0 and 3.0 are not supported by the class when the SSLProvider is set to internal. To use SSL 2.0 or SSL 3.0, the platform security API must have the protocols enabled and SSLProvider needs to be set to platform.

**SSLEnableRenegotiation**: Whether the renegotiation_info SSL extension is supported.This configuration setting specifies whether the renegotiation_info SSL extension will be used in the request when using the internal security API. This configuration setting is *false* by default, but it can be set to *true* to enable the extension.

This configuration setting is applicable only when SSLProvider is set to *Internal*.

**SSLIncludeCertChain**: Whether the entire certificate chain is included in the SSLServerAuthentication event.This configuration setting specifies whether the Encoded parameter of the SSLServerAuthentication event contains the full certificate chain. By default this value is False and only the leaf certificate will be present in the Encoded parameter of the SSLServerAuthentication event.

If set to True, all certificates returned by the server will be present in the Encoded parameter of the SSLServerAuthentication event. This includes the leaf certificate, any intermediate certificate, and the root certificate.

Note: When SSLProvider is set to *Internal* this value is automatically set to *true*. This is needed for proper validation when using the internal provider.

**SSLKeyLogFile**: The location of a file where per-session secrets are written for debugging purposes.This configuration setting optionally specifies the full path to a file on disk where per-session secrets are stored for debugging purposes.

When set, the class will save the session secrets in the same format as the SSLKEYLOGFILE environment variable functionality used by most major browsers and tools, such as Chrome, Firefox, and cURL. This file can then be used in tools such as Wireshark to decrypt TLS traffic for debugging purposes. When writing to this file, the class will only append, it will not overwrite previous values.

NOTE: This configuration setting is applicable only when SSLProvider is set to *Internal*.

**SSLNegotiatedCipher**: Returns the negotiated cipher suite.This configuration setting returns the cipher suite negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedCipher[connId]");
```

**SSLNegotiatedCipherStrength**: Returns the negotiated cipher suite strength.This configuration setting returns the strength of the cipher suite negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedCipherStrength[connId]");
```

**SSLNegotiatedCipherSuite**: Returns the negotiated cipher suite.This configuration setting returns the cipher suite negotiated during the SSL handshake represented as a single string.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedCipherSuite[connId]");
```

**SSLNegotiatedKeyExchange**: Returns the negotiated key exchange algorithm.This configuration setting returns the key exchange algorithm negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedKeyExchange[connId]");
```

**SSLNegotiatedKeyExchangeStrength**: Returns the negotiated key exchange algorithm strength.This configuration setting returns the strength of the key exchange algorithm negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedKeyExchangeStrength[connId]");
```

**SSLNegotiatedVersion**: Returns the negotiated protocol version.This configuration setting returns the protocol version negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedVersion[connId]");
```

**SSLServerCACerts**: A newline separated list of CA certificates to use during SSL server certificate validation.This configuration setting is only used by client components (e.g., TCPClient) see [SSLClientCACerts](#SSLClientCACerts) for server components (e.g., TCPServer). This configuration setting can be used to optionally specify one or more CA certificates to be used when connecting to the server and verifying the server certificate. When verifying the server's certificate, the certificates trusted by the system will be used as part of the verification process. If the server's CA certificates are not installed to the trusted system store, they may be specified here so they are included when performing the verification process. This configuration setting should be set only if the server's CA certificates are not already trusted on the system and cannot be installed to the trusted system store.

The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

```text
-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----
```

**SSLTrustManagerFactoryAlgorithm**: The algorithm to be used to create a TrustManager through TrustManagerFactory.Possible values include SunX509. This is the parameter "algorithm" inside the TrustManagerFactory.getInstance(algorithm) call.

**TLS12SignatureAlgorithms**: Defines the allowed TLS 1.2 signature algorithms when SSLProvider is set to Internal.This configuration setting specifies the allowed server certificate signature algorithms when SSLProvider is set to *Internal* and [SSLEnabledProtocols](#SSLEnabledProtocols) is set to allow TLS 1.2.

When specified the class will verify that the server certificate signature algorithm is among the values specified in this configuration setting. If the server certificate signature algorithm is unsupported, the class throws an exception.

The format of this value is a comma-separated list of hash-signature combinations. For instance:

```csharp
component.SSLProvider = TCPClientSSLProviders.sslpInternal;
component.Config("SSLEnabledProtocols=3072"); //TLS 1.2
component.Config("TLS12SignatureAlgorithms=sha256-rsa,sha256-dsa,sha1-rsa,sha1-dsa");
```

 The default value for this configuration setting is *sha512-ecdsa,sha512-rsa,sha512-dsa,sha384-ecdsa,sha384-rsa,sha384-dsa,sha256-ecdsa,sha256-rsa,sha256-dsa,sha224-ecdsa,sha224-rsa,sha224-dsa,sha1-ecdsa,sha1-rsa,sha1-dsa*.

To not restrict the server's certificate signature algorithm, specify an empty string as the value for this configuration setting, which will cause the signature_algorithms TLS 1.2 extension to not be sent.

**TLS12SupportedGroups**: The supported groups for ECC.This configuration setting specifies a comma-separated list of named groups used in TLS 1.2 for ECC.

The default value is *ecdhe_secp256r1,ecdhe_secp384r1,ecdhe_secp521r1*.

When using TLS 1.2 and SSLProvider is set to *Internal*, the values refer to the supported groups for ECC. The following values are supported:

- "ecdhe_secp256r1" (default)
- "ecdhe_secp384r1" (default)
- "ecdhe_secp521r1" (default)

**TLS13KeyShareGroups**: The groups for which to pregenerate key shares.This configuration setting specifies a comma-separated list of named groups used in TLS 1.3 for key exchange. The groups specified here will have key share data pregenerated locally before establishing a connection. This can prevent an additional roundtrip during the handshake if the group is supported by the server.

The default value is set to balance common supported groups and the computational resources required to generate key shares. As a result, only some groups are included by default in this configuration setting.

NOTE: All supported groups can always be used during the handshake even if not listed here, but if a group is used that is not present in this list, it will incur an additional roundtrip and time to generate the key share for that group.

In most cases, this configuration setting does not need to be modified. This should be modified only if there is a specific reason to do so.

The default value is *ecdhe_x25519,ecdhe_secp256r1,ecdhe_secp384r1,ffdhe_2048,ffdhe_3072*

The values are ordered from most preferred to least preferred. The following values are supported:

- "ecdhe_x25519" (default)
- "ecdhe_x448"
- "ecdhe_secp256r1" (default)
- "ecdhe_secp384r1" (default)
- "ecdhe_secp521r1"
- "ffdhe_2048" (default)
- "ffdhe_3072" (default)
- "ffdhe_4096"
- "ffdhe_6144"
- "ffdhe_8192"

**TLS13SignatureAlgorithms**: The allowed certificate signature algorithms.This configuration setting holds a comma-separated list of allowed signature algorithms. Possible values include the following:

- "ed25519" (default)
- "ed448" (default)
- "ecdsa_secp256r1_sha256" (default)
- "ecdsa_secp384r1_sha384" (default)
- "ecdsa_secp521r1_sha512" (default)
- "rsa_pkcs1_sha256" (default)
- "rsa_pkcs1_sha384" (default)
- "rsa_pkcs1_sha512" (default)
- "rsa_pss_sha256" (default)
- "rsa_pss_sha384" (default)
- "rsa_pss_sha512" (default)

 The default value is *rsa_pss_sha256,rsa_pss_sha384,rsa_pss_sha512,rsa_pkcs1_sha256,rsa_pkcs1_sha384,rsa_pkcs1_sha512,ecdsa_secp256r1_sha256,ecdsa_secp384r1_sha384,ecdsa_secp521r1_sha512,ed25519,ed448*. This configuration setting is applicable only when [SSLEnabledProtocols](#SSLEnabledProtocols) includes TLS 1.3.

**TLS13SupportedGroups**: The supported groups for (EC)DHE key exchange.This configuration setting specifies a comma-separated list of named groups used in TLS 1.3 for key exchange. This configuration setting should be modified only if there is a specific reason to do so.

The default value is *ecdhe_x25519,ecdhe_x448,ecdhe_secp256r1,ecdhe_secp384r1,ecdhe_secp521r1,ffdhe_2048,ffdhe_3072,ffdhe_4096,ffdhe_6144,ffdhe_8192,mlkem_512,mlkem_768,mlkem_1024,x25519_mlkem_768,secp256r1_mlkem_768*

The values are ordered from most preferred to least preferred. The following values are supported:

- "ecdhe_x25519" (default)
- "ecdhe_x448" (default)
- "ecdhe_secp256r1" (default)
- "ecdhe_secp384r1" (default)
- "ecdhe_secp521r1" (default)
- "ffdhe_2048" (default)
- "ffdhe_3072" (default)
- "ffdhe_4096" (default)
- "ffdhe_6144" (default)
- "ffdhe_8192" (default)
- "mlkem_512" (default)
- "mlkem_768" (default)
- "mlkem_1024" (default)
- "x25519_mlkem_768" (default)
- "secp256r1_mlkem_768" (default)

Post-quantum algorithms (*mlkem_512,mlkem_768,mlkem_1024,x25519_mlkem_768,secp256r1_mlkem_768*) in our components rely on the operating system's underlying cryptographic primitives. The following platforms are currently supported:

-  Windows Server 2025
-  Windows 11 24H2
-  Windows 11 25H2

### Base Config Settings

**BuildInfo**: Information about the product's build.When queried, this setting will return a string containing information about the product's build.

**GUIAvailable**: Whether or not a message loop is available for processing events.In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The class will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting [GUIAvailable](#GUIAvailable) to *false* will ensure that the class does not attempt to process external events.

**LicenseInfo**: Information about the current license.When queried, this setting will return a string containing information about the license this instance of a class is using. It will return the following information:

- Product: The product the license is for.
- Product Key: The key the license was generated from.
- License Source: Where the license was found (e.g., RuntimeLicense, License File).
- License Type: The type of license installed (e.g., Royalty Free, Single Server).
- Last Valid Build: The last valid build number for which the license will work.

**MaskSensitiveData**: Whether sensitive data is masked in log messages.In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to *true* to mask sensitive data. The default is *true*.

**UseDaemonThreads**: Whether threads created by the class are daemon threads.If set to True (default), when the class creates a thread, the thread's Daemon property will be explicitly set to True. When set to False, the class will not set the Daemon property on the created thread. The default value is True.

**UseFIPSCompliantAPI**: Tells the class whether or not to use FIPS certified APIs.When set to *true*, the class will utilize the underlying operating system's certified APIs. Java editions, regardless of OS, utilize Bouncy Castle Federal Information Processing Standards (FIPS), while all other Windows editions make use of Microsoft security libraries.

The Java edition requires installation of the FIPS-certified Bouncy Castle library regardless of the target operating system. This can be downloaded from [https://www.bouncycastle.org/fips-java/](https://www.bouncycastle.org/fips-java/). Only the "Provider" library is needed. The jar file should then be installed in a JRE search path.

The following classes must be imported in the application in which the component will be used:

```text
import java.security.Security;
import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider;
```

The Bouncy Castle provider must be added as a valid provider and must also be configured to operate in FIPS mode:

```text
System.setProperty("org.bouncycastle.fips.approved_only","true");
Security.addProvider(new BouncyCastleFipsProvider());
```

When [UseFIPSCompliantAPI](#UseFIPSCompliantAPI) is *true*, Secure Sockets Layer (SSL)-enabled classes can optionally be configured to use the Transport Layer Security (TLS) Bouncy Castle library. When SSLProvider is set to *sslpAutomatic* (default) or *sslpInternal*, an internal TLS implementation is used, but all cryptographic operations are offloaded to the Bouncy Castle FIPS provider to achieve FIPS-compliant operation. If SSLProvider is set to *sslpPlatform*, the Bouncy Castle JSSE will be used in place of the internal TLS implementation.

To enable the use of the Bouncy Castle JSSE take the following steps in addition to the steps above. Both the Bouncy Castle FIPS provider and the Bouncy Castle JSSE must be configured to use the Bouncy Castle TLS library in FIPS mode. Obtain the Bouncy Castle TLS library from [https://www.bouncycastle.org/fips-java/](https://www.bouncycastle.org/fips-java/). The jar file should then be installed in a JRE search path.

The following classes must be imported in the application in which the component will be used:

```text
import java.security.Security;
import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider;

//required to use BCJSSE when SSLProvider is set to sslpPlatform
import org.bouncycastle.jsse.provider.BouncyCastleJsseProvider;
```

The Bouncy Castle provider must be added as a valid provider and also must be configured to operate in FIPS mode:

```text
System.setProperty("org.bouncycastle.fips.approved_only","true");
Security.addProvider(new BouncyCastleFipsProvider());

//required to use BCJSSE when SSLProvider is set to sslpPlatform
Security.addProvider(new BouncyCastleJsseProvider("fips:BCFIPS"));

//optional - configure logging level of BCJSSE
Logger.getLogger("org.bouncycastle.jsse").setLevel(java.util.logging.Level.OFF);

//configure the class to use BCJSSE
component.setSSLProvider(1); //platform
component.config("UseFIPSCompliantAPI=true");
```

 NOTE: TLS 1.3 support requires the Bouncy Castle TLS library version 1.0.14 or later.

FIPS mode can be enabled by setting the *UseFIPSCompliantAPI* configuration setting to *true*. This is a static setting that applies to all instances of all classes of the toolkit within the process. It is recommended to enable or disable this setting once before the component has been used to establish a connection. Enabling FIPS while an instance of the component is active and connected may result in unexpected behavior.

For more details, please see the [FIPS 140-2 Compliance](https://www.nsoftware.com/kb/articles/fips.rst) article.

NOTE: Enabling FIPS compliance requires a special license; please contact [sales@nsoftware.com](mailto:sales@nsoftware.com) for details.

**UseInternalSecurityAPI**: Whether or not to use the system security libraries or an internal implementation. When set to *false*, the class will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this configuration setting to *true* tells the class to use the internal implementation instead of using the system security libraries.

 This setting is set to *false* by default on all platforms.

**UseVirtualThreads**: Whether threads created by the class use virtual threads instead of platform threads.If set to *true*, when the class creates a thread, it will be created as a virtual thread instead of a platform thread. Virtual threads are lightweight threads managed by the JVM that are multiplexed onto a small pool of carrier threads, significantly reducing memory usage and platform thread count under high-concurrency workloads. Requires Java 24 or later. The default value is *false*.

# Trappable Errors ([SFTPServer](#sftpserver-class) Class)

### SFTPServer Errors

|  |  |
| --- | --- |
| 118 | Firewall error. Error description contains detailed information. |
| 2001 | The specified path is invalid. |
| 2002 | An I/O error occurred. |
| 2003 | The file attributes could not be set. |

### SSHServer Errors

|  |  |
| --- | --- |
| 1201 | Could not forward connection. A detailed message follows. |
| 1202 | Could not forward connection/channel data. A detailed message follows. |
| 1300 | Could not authenticate client. |
| 1301 | No server certificate was specified or no private key found. |

### TCPServer Errors

|  |  |
| --- | --- |
| 100 | You cannot change the RemotePort at this time. A connection is in progress. |
| 101 | You cannot change the RemoteHost at this time. A connection is in progress. |
| 102 | The RemoteHost address is invalid (0.0.0.0). |
| 104 | TCPServer is already listening. |
| 106 | Cannot change [LocalPort](#localport-property-sftpserver-class) when TCPServer is listening. |
| 107 | Cannot change [LocalHost](#localhost-property-sftpserver-class) when TCPServer is listening. |
| 108 | Cannot change [MaxConnections](#MaxConnections) when TCPServer is listening. |
| 112 | You cannot change [MaxLineLength](#MaxLineLength) at this time. A connection is in progress. |
| 116 | RemotePort cannot be zero. Please specify a valid service port number. |
| 126 | Invalid ConnectionId. |
| 135 | Operation would block. |

### TCP/IP Errors

|  |  |
| --- | --- |
| 10004 | [10004] Interrupted system call. |
| 10009 | [10009] Bad file number. |
| 10013 | [10013] Access denied. |
| 10014 | [10014] Bad address. |
| 10022 | [10022] Invalid argument. |
| 10024 | [10024] Too many open files. |
| 10035 | [10035] Operation would block. |
| 10036 | [10036] Operation now in progress. |
| 10037 | [10037] Operation already in progress. |
| 10038 | [10038] Socket operation on nonsocket. |
| 10039 | [10039] Destination address required. |
| 10040 | [10040] Message is too long. |
| 10041 | [10041] Protocol wrong type for socket. |
| 10042 | [10042] Bad protocol option. |
| 10043 | [10043] Protocol is not supported. |
| 10044 | [10044] Socket type is not supported. |
| 10045 | [10045] Operation is not supported on socket. |
| 10046 | [10046] Protocol family is not supported. |
| 10047 | [10047] Address family is not supported by protocol family. |
| 10048 | [10048] Address already in use. |
| 10049 | [10049] Cannot assign requested address. |
| 10050 | [10050] Network is down. |
| 10051 | [10051] Network is unreachable. |
| 10052 | [10052] Net dropped connection or reset. |
| 10053 | [10053] Software caused connection abort. |
| 10054 | [10054] Connection reset by peer. |
| 10055 | [10055] No buffer space available. |
| 10056 | [10056] Socket is already connected. |
| 10057 | [10057] Socket is not connected. |
| 10058 | [10058] Cannot send after socket shutdown. |
| 10059 | [10059] Too many references, cannot splice. |
| 10060 | [10060] Connection timed out. |
| 10061 | [10061] Connection refused. |
| 10062 | [10062] Too many levels of symbolic links. |
| 10063 | [10063] File name is too long. |
| 10064 | [10064] Host is down. |
| 10065 | [10065] No route to host. |
| 10066 | [10066] Directory is not empty |
| 10067 | [10067] Too many processes. |
| 10068 | [10068] Too many users. |
| 10069 | [10069] Disc Quota Exceeded. |
| 10070 | [10070] Stale NFS file handle. |
| 10071 | [10071] Too many levels of remote in path. |
| 10091 | [10091] Network subsystem is unavailable. |
| 10092 | [10092] WINSOCK DLL Version out of range. |
| 10093 | [10093] Winsock is not loaded yet. |
| 11001 | [11001] Host not found. |
| 11002 | [11002] Nonauthoritative 'Host not found' (try again or check DNS setup). |
| 11003 | [11003] Nonrecoverable errors: FORMERR, REFUSED, NOTIMP. |
| 11004 | [11004] Valid name, no data record (check DNS setup). |