# SSHReverseTunnel Component

The SSHReverseTunnel component provides a simple way to establish a reverse tunnel with a Secure Shell (SSH) host.

## Syntax

```text
nsoftware.IPWorksSSH.SSHReverseTunnel
```

## Remarks

The SSHReverseTunnel component may be used to establish a reverse tunnel with a Secure Shell (SSH) host. The SSH host will listen for incoming connections on the specified port and forward traffic to the component through the SSH tunnel.

The [SSHHost](#sshhost-property-sshreversetunnel-component) and [SSHPort](#sshport-property-sshreversetunnel-component) properties specify which Secure Shell (SSH) server to use. The [SSHUser](#sshuser-property-sshreversetunnel-component) and [SSHPassword](#sshpassword-property-sshreversetunnel-component) properties allow the client to authenticate itself with the server. The [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) event or [SSHAcceptServerHostKey](#sshacceptserverhostkey-property-sshreversetunnel-component) property allow you to check the server identity. Finally, the [SSHStatus](#sshstatus-event-sshreversetunnel-component) event provides information about the SSH handshake.

To begin, call [SSHLogon](#sshlogon-method-sshreversetunnel-component) to connect to the SSH host. After this method returns, the connection to the SSH server is successfully established. Call [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) to establish a reverse tunnel. This method takes parameters to tell the SSH host on which port to listen.

The component has two modes that allow data to be dealt with directly from the events, or automatically forwarded on to a different endpoint.

**Event Based Operation**

In this mode, any data received by the component over the tunnel causes the events of the component to fire. For instance:

```text
SSHReverseTunnel.RequestForwarding("0.0.0.0", 777, "", 0);
```

In the above code, forwarding is requested from port 777 on the [SSHHost](#sshhost-property-sshreversetunnel-component). Any data received on port 777 by the [SSHHost](#sshhost-property-sshreversetunnel-component) will be sent to the component. In the above code, the last two parameters are empty and 0, indicating to the component that no local forwarding is requested.

Once [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) returns, the Secure Shell (SSH) reverse tunnel is established. Any connection made to the SSH host on the specified port will then trigger the component's events to fire, allowing you to handle the connection request and data.

When a client connects to the SSH host on the specified port, the [SSHChannelOpenRequest](#sshchannelopenrequest-event-sshreversetunnel-component) event will fire. Within this event, choose to accept or reject the connection by setting the *Accept* parameter. This event contains details about the connection that may be used when determining whether to accept the connection.

After the channel is established, data are received through the [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) event. Call the [SendChannelData](#sendchanneldata-method-sshreversetunnel-component) method to send data over the channel, and call the [CloseChannel](#closechannel-method-sshreversetunnel-component) method to close the channel.

**Local Forwarding**

In this mode, any data received by the component is automatically forwarded to a separate endpoint. This allows the component to act as a sort of proxy. There is no need to handle data directly in this case. For instance:

```text
SSHReverseTunnel.RequestForwarding("0.0.0.0", 777, "nsoftware.com", 80);
```

In the above code, forwarding is requested from port 777 on [SSHHost](#sshhost-property-sshreversetunnel-component). The component is instructed to establish a connection to "nsoftware.com" on port 80 when a client connects to [SSHHost](#sshhost-property-sshreversetunnel-component) on port 777. Any data received from the client connected to [SSHHost](#sshhost-property-sshreversetunnel-component) on port 777 will automatically be forwarded to "nsoftware.com" on port 80. Any data received back from "nsoftware.com" on port 80 will be sent back to the connected client.

In this mode, data may flow freely from the client connected to the [SSHHost](#sshhost-property-sshreversetunnel-component) to the endpoint specified in the [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) method without any additional code required.

NOTE: The following events are applicable when a connection is made to the SSH host:

- [SSHChannelClosed](#sshchannelclosed-event-sshreversetunnel-component)
- [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component)
- [SSHChannelEOF](#sshchanneleof-event-sshreversetunnel-component)
- [SSHChannelOpened](#sshchannelopened-event-sshreversetunnel-component)
- [SSHChannelOpenRequest](#sshchannelopenrequest-event-sshreversetunnel-component)
- [SSHChannelReadyToSend](#sshchannelreadytosend-event-sshreversetunnel-component)
- [SSHChannelRequested](#sshchannelrequested-event-sshreversetunnel-component)

To stop a previously established reverse tunnel, call the [CancelForwarding](#cancelforwarding-method-sshreversetunnel-component) method.

## Property List

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

|  |  |
| --- | --- |
| [Channels](#channels-property-sshreversetunnel-component) | A collection of currently open channels. |
| [Connected](#connected-property-sshreversetunnel-component) | The component to be connected. |
| [Firewall](#firewall-property-sshreversetunnel-component) | A set of properties related to firewall access. |
| [LocalHost](#localhost-property-sshreversetunnel-component) | The name of the local host or user-assigned IP interface through which connections are initiated or accepted. |
| [LocalPort](#localport-property-sshreversetunnel-component) | The TCP port in the local host where the component binds. |
| [SSHAcceptServerHostKey](#sshacceptserverhostkey-property-sshreversetunnel-component) | Instructs the component to accept the server host key that matches the supplied key. |
| [SSHAuthMode](#sshauthmode-property-sshreversetunnel-component) | The authentication method to be used with the component when calling [SSHLogon](#sshlogon-method-sshreversetunnel-component) . |
| [SSHCert](#sshcert-property-sshreversetunnel-component) | A certificate to be used for authenticating the [SSHUser](#sshuser-property-sshreversetunnel-component) . |
| [SSHCompressionAlgorithms](#sshcompressionalgorithms-property-sshreversetunnel-component) | The comma-separated list containing all allowable compression algorithms. |
| [SSHEncryptionAlgorithms](#sshencryptionalgorithms-property-sshreversetunnel-component) | The comma-separated list containing all allowable encryption algorithms. |
| [SSHHost](#sshhost-property-sshreversetunnel-component) | The address of the Secure Shell (SSH) host. |
| [SSHPassword](#sshpassword-property-sshreversetunnel-component) | The password for Secure Shell (SSH) password-based authentication. |
| [SSHPort](#sshport-property-sshreversetunnel-component) | The port on the Secure Shell (SSH) server where the SSH service is running; by default, 22. |
| [SSHUser](#sshuser-property-sshreversetunnel-component) | The username for Secure Shell (SSH) authentication. |
| [Timeout](#timeout-property-sshreversetunnel-component) | This property includes the timeout for the component. |

## Method List

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

|  |  |
| --- | --- |
| [CancelForwarding](#cancelforwarding-method-sshreversetunnel-component) | Requests the server to stop forwarding a remote Transmission Control Protocol (TCP)/IP port. |
| [CloseChannel](#closechannel-method-sshreversetunnel-component) | Closes an existing SSHChannel . |
| [Config](#config-method-sshreversetunnel-component) | Sets or retrieves a configuration setting. |
| [DecodePacket](#decodepacket-method-sshreversetunnel-component) | Decodes a hex-encoded Secure Shell (SSH) packet |
| [DoEvents](#doevents-method-sshreversetunnel-component) | This method processes events from the internal message queue. |
| [EncodePacket](#encodepacket-method-sshreversetunnel-component) | Hex encodes a Secure Shell (SSH) packet. |
| [ExchangeKeys](#exchangekeys-method-sshreversetunnel-component) | Causes the component to exchange a new set of session keys with the [SSHHost](#sshhost-property-sshreversetunnel-component) . |
| [GetSSHParam](#getsshparam-method-sshreversetunnel-component) | Reads a field from a Secure Shell (SSH) packet's payload. |
| [GetSSHParamBytes](#getsshparambytes-method-sshreversetunnel-component) | Reads a field from a Secure Shell (SSH) packet's payload. |
| [Interrupt](#interrupt-method-sshreversetunnel-component) | This method interrupts the current method. |
| [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) | Requests the server to forward a remote Transmission Control Protocol (TCP)/IP port. |
| [Reset](#reset-method-sshreversetunnel-component) | This method will reset the component. |
| [SendChannelData](#sendchanneldata-method-sshreversetunnel-component) | Sends data over a Secure Shell (SSH) channel. |
| [SetSSHParam](#setsshparam-method-sshreversetunnel-component) | Writes a field to the end of a payload. |
| [SSHLogoff](#sshlogoff-method-sshreversetunnel-component) | Logs off from the Secure Shell (SSH) server. |
| [SSHLogon](#sshlogon-method-sshreversetunnel-component) | Logs on to the [SSHHost](#sshhost-property-sshreversetunnel-component) using the current [SSHUser](#sshuser-property-sshreversetunnel-component) and [SSHPassword](#sshpassword-property-sshreversetunnel-component) . |

## Event List

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

|  |  |
| --- | --- |
| [Connected](#connected-event-sshreversetunnel-component) | Fired immediately after a connection completes (or fails). |
| [ConnectionStatus](#connectionstatus-event-sshreversetunnel-component) | Fired to indicate changes in the connection state. |
| [Disconnected](#disconnected-event-sshreversetunnel-component) | Fired when a connection is closed. |
| [Error](#error-event-sshreversetunnel-component) | Fired when information is available about errors during data delivery. |
| [Log](#log-event-sshreversetunnel-component) | Fired once for each log message. |
| [ReconnectAttempt](#reconnectattempt-event-sshreversetunnel-component) | Fired when attempting to reconnect. |
| [SSHChannelClosed](#sshchannelclosed-event-sshreversetunnel-component) | Fired when a channel is closed. |
| [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) | Fired when the [SSHHost](#sshhost-property-sshreversetunnel-component) sends channel data to the client. |
| [SSHChannelEOF](#sshchanneleof-event-sshreversetunnel-component) | Fired when the remote peer signals the end of the data stream for the channel. |
| [SSHChannelOpened](#sshchannelopened-event-sshreversetunnel-component) | Fired when a channel is successfully opened. |
| [SSHChannelOpenRequest](#sshchannelopenrequest-event-sshreversetunnel-component) | Fired when the peer attempts to open a new channel. |
| [SSHChannelReadyToSend](#sshchannelreadytosend-event-sshreversetunnel-component) | Fired when the component is ready to send data. |
| [SSHChannelRequest](#sshchannelrequest-event-sshreversetunnel-component) | Fired when the [SSHHost](#sshhost-property-sshreversetunnel-component) sends a channel request to the client. |
| [SSHChannelRequested](#sshchannelrequested-event-sshreversetunnel-component) | Fired if the SSHChannelRequest was successful; any further processing for the channel request should be done here. |
| [SSHCustomAuth](#sshcustomauth-event-sshreversetunnel-component) | Fired when the component is doing a custom authentication. |
| [SSHKeyboardInteractive](#sshkeyboardinteractive-event-sshreversetunnel-component) | Fired when the component receives a request for user input from the server. |
| [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) | Fired after the server presents its public key to the client. |
| [SSHStatus](#sshstatus-event-sshreversetunnel-component) | Fired to track the progress of the secure connection. |

## Config Settings

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

|  |  |
| --- | --- |
| [AutoReconnect](#AutoReconnect) | Whether to automatically reconnect. |
| [DefaultChannelIdleTimeout](#DefaultChannelIdleTimeout) | The inactivity timeout for channels. |
| [ForwardedPort](#ForwardedPort) | The remote port which is forwarded. |
| [ForwardingLocalHost](#ForwardingLocalHost) | The interface on which to bind when forwarding data. |
| [MaxChannelCount](#MaxChannelCount) | Maximum number of open channels. |
| [MaxChannelTransferRate\[ChannelId\]](#MaxChannelTransferRate[ChannelId]) | The transfer rate limit for a channel in bytes per second. |
| [MaxRetryCount](#MaxRetryCount) | The maximum number of retries when reconnecting. |
| [RetryInterval](#RetryInterval) | The interval in seconds between reconnect attempts. |
| [ChannelDataEOL\[ChannelId\]](#ChannelDataEOL[ChannelId]) | Used to break the incoming data stream into chunks. |
| [ChannelDataEOLFound\[ChannelId\]](#ChannelDataEOLFound[ChannelId]) | Determines if ChannelDataEOL was found. |
| [ClientSSHVersionString](#ClientSSHVersionString) | The SSH version string used by the component. |
| [ConnectAndLogin](#ConnectAndLogin) | Whether the component performs a full SSH login. |
| [DoNotRepeatAuthMethods](#DoNotRepeatAuthMethods) | Whether the component will repeat authentication methods during multifactor authentication. |
| [EnablePageantAuth](#EnablePageantAuth) | Whether to use a key stored in Pageant to perform client authentication. |
| [KerberosDelegation](#KerberosDelegation) | If true, asks for credentials with delegation enabled during authentication. |
| [KerberosRealm](#KerberosRealm) | The fully qualified domain name of the Kerberos Realm to use for GSSAPI authentication. |
| [KerberosSPN](#KerberosSPN) | The Kerberos Service Principal Name of the SSH host. |
| [KeyRenegotiationThreshold](#KeyRenegotiationThreshold) | Sets the threshold for the SSH Key Renegotiation. |
| [LogLevel](#LogLevel) | Specifies the level of detail that is logged. |
| [MaxChannelDataLength\[ChannelId\]](#MaxChannelDataLength[ChannelId]) | The maximum amount of data to accumulate when no ChannelDataEOL is found. |
| [MaxPacketSize](#MaxPacketSize) | The maximum packet size of the channel, in bytes. |
| [MaxWindowSize](#MaxWindowSize) | The maximum window size allowed for the channel, in bytes. |
| [NegotiatedStrictKex](#NegotiatedStrictKex) | Returns whether strict key exchange was negotiated to be used. |
| [PasswordPrompt](#PasswordPrompt) | The text of the password prompt used in keyboard-interactive authentication. |
| [PreferredDHGroupBits](#PreferredDHGroupBits) | The size (in bits) of the preferred modulus (p) to request from the server. |
| [RecordLength](#RecordLength) | The length of received data records. |
| [ServerSSHVersionString](#ServerSSHVersionString) | The remote host's SSH version string. |
| [SignedSSHCert](#SignedSSHCert) | The CA signed client public key used when authenticating. |
| [SSHAcceptAnyServerHostKey](#SSHAcceptAnyServerHostKey) | If set the component will accept any key presented by the server. |
| [SSHAcceptServerCAKey](#SSHAcceptServerCAKey) | The CA public key that signed the server's host key. |
| [SSHAcceptServerHostKeyFingerPrint](#SSHAcceptServerHostKeyFingerPrint) | The fingerprint(s) of the server host keys to accept. |
| [SSHFingerprintEncoding](#SSHFingerprintEncoding) | Specifies the encoding used when displaying the SSH host key fingerprint. |
| [SSHFingerprintHashAlgorithm](#SSHFingerprintHashAlgorithm) | The algorithm used to calculate the fingerprint. |
| [SSHFingerprintMD5](#SSHFingerprintMD5) | The server hostkey's MD5 fingerprint. |
| [SSHFingerprintSHA1](#SSHFingerprintSHA1) | The server hostkey's SHA1 fingerprint. |
| [SSHFingerprintSHA256](#SSHFingerprintSHA256) | The server hostkey's SHA256 fingerprint. |
| [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. |
| [SSHKeyRenegotiate](#SSHKeyRenegotiate) | Causes the component to renegotiate the SSH keys. |
| [SSHMacAlgorithms](#SSHMacAlgorithms) | Specifies the supported Mac algorithms. |
| [SSHPubKeyAuthSigAlgorithms](#SSHPubKeyAuthSigAlgorithms) | Specifies the enabled signature algorithms that may be used when attempting 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. |
| [TryAllAvailableAuthMethods](#TryAllAvailableAuthMethods) | If set to true, the component will try all available authentication methods. |
| [UseStrictKeyExchange](#UseStrictKeyExchange) | Specifies how strict key exchange is supported. |
| [WaitForChannelClose](#WaitForChannelClose) | Whether to wait for channels to be closed before disconnected. |
| [WaitForServerDisconnect](#WaitForServerDisconnect) | Whether to wait for the server to close the connection. |
| [CloseStreamAfterTransfer](#CloseStreamAfterTransfer) | If true, the component will close the upload or download stream after the transfer. |
| [ConnectionTimeout](#ConnectionTimeout) | Sets a separate timeout value for establishing a connection. |
| [FirewallAutoDetect](#FirewallAutoDetect) | Tells the component whether or not to automatically detect and use firewall system settings, if available. |
| [FirewallHost](#FirewallHost) | Name or IP address of firewall (optional). |
| [FirewallHTTPVersion](#FirewallHTTPVersion) | The HTTP version to be used when connecting through a tunneling proxy. |
| [FirewallListener](#FirewallListener) | If true, the component binds to a SOCKS firewall as a server (TCPClient only). |
| [FirewallPassword](#FirewallPassword) | Password to be used if authentication is to be used when connecting through the firewall. |
| [FirewallPort](#FirewallPort) | The TCP port for the FirewallHost;. |
| [FirewallType](#FirewallType) | Determines the type of firewall to connect through. |
| [FirewallUser](#FirewallUser) | A user name if authentication is to be used connecting through a firewall. |
| [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. |
| [Linger](#Linger) | When set to True, connections are terminated gracefully. |
| [LingerTime](#LingerTime) | Time in seconds to have the connection linger. |
| [LocalHost](#LocalHost) | The name of the local host through which connections are initiated or accepted. |
| [LocalPort](#LocalPort) | The port in the local host where the component binds. |
| [MaxLineLength](#MaxLineLength) | The maximum amount of data to accumulate when no EOL is found. |
| [MaxTransferRate](#MaxTransferRate) | The transfer rate limit in bytes per second. |
| [ProxyExceptionsList](#ProxyExceptionsList) | A semicolon separated list of hosts and IPs to bypass when using a proxy. |
| [TCPKeepAlive](#TCPKeepAlive) | Determines whether or not the keep alive socket option is enabled. |
| [TcpNoDelay](#TcpNoDelay) | Whether or not to delay when sending packets. |
| [UseIPv6](#UseIPv6) | Whether to use IPv6. |
| [UseNTLMv2](#UseNTLMv2) | Whether to use NTLM V2. |
| [AbsoluteTimeout](#AbsoluteTimeout) | Determines whether timeouts are inactivity timeouts or absolute timeouts. |
| [FirewallData](#FirewallData) | Used to send extra data to the firewall. |
| [InBufferSize](#InBufferSize) | The size in bytes of the incoming queue of the socket. |
| [OutBufferSize](#OutBufferSize) | The size in bytes of the outgoing queue of the socket. |
| [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. |
| [UseFIPSCompliantAPI](#UseFIPSCompliantAPI) | Tells the component whether or not to use FIPS certified APIs. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |

# Channels Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

A collection of currently open channels.

## Syntax

```text
public SSHRTChannelMap Channels { get; }
```

## Remarks

This property is a collection of established channels. When a client connects to an existing reverse tunnel, a new channel is requested and added to this collection. This collection is a hashtable for which the channel's Id string is used as the key to the desired Secure Shell (SSH) channel object.

**Example. Sending Data to a Channel**

```text
channels["1"].DataToSend = "channel specific data";
```

This property is read-only.

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

# Connected Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The component to be connected.

## Syntax

```text
public bool Connected { get; }
```

## Default Value

False

## Remarks

This property is used to determine whether or not the component is connected to the remote host. Use the [SSHLogon](#sshlogon-method-sshreversetunnel-component) and [SSHLogoff](#sshlogoff-method-sshreversetunnel-component) methods to manage the connection.

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

# Firewall Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

A set of properties related to firewall access.

## Syntax

```text
public Firewall Firewall { get; set; }
```

## Remarks

This is a [Firewall](#firewall-type)-type property, which contains fields describing the firewall through which the component will attempt to connect.

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

# LocalHost Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

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

## Syntax

```text
public string LocalHost { get; set; }
```

## 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 component initiate connections (or accept in the case of server components) 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 component 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 ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The TCP port in the local host where the component binds.

## Syntax

```text
public int LocalPort { get; set; }
```

## Default Value

0

## Remarks

This property must be set before a connection is attempted. It instructs the component to bind to a specific port (or communication endpoint) in the local machine.

Setting this property to 0 (default) enables the system to choose an open port at random. The chosen port will be returned by the LocalPort property after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set this property when a connection is active will generate an error.

This property is useful when trying to connect to services that require a trusted port on the client side.

# SSHAcceptServerHostKey Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Instructs the component to accept the server host key that matches the supplied key.

## Syntax

```text
public Certificate SSHAcceptServerHostKey { get; set; }
```

## Remarks

If the host key that will be used by the server is known in advance, this property may be set to accept the expected key. Otherwise, the [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) event should be trapped, and the key should be accepted or refused in the event.

If this property is not set and the [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) event is not trapped, the server will not be authenticated and the connection will be terminated by the client.

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

# SSHAuthMode Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The authentication method to be used with the component when calling [SSHLogon](#sshlogon-method-sshreversetunnel-component) .

## Syntax

```text
public SSHReverseTunnelSSHAuthModes SSHAuthMode { get; set; }
enum SSHReverseTunnelSSHAuthModes {
  amNone,
  amMultiFactor,
  amPassword,
  amPublicKey,
  amKeyboardInteractive,
  amGSSAPIWithMic,
  amGSSAPIKeyex,
  amCustom
}
```

## Default Value

2

## Remarks

The Secure Shell (SSH) Authentication specification (RFC 4252) specifies multiple methods by which a user can be authenticated by an SSH server. When a call is made to [SSHLogon](#sshlogon-method-sshreversetunnel-component), the component will connect to the SSH server and establish the security layer. After the connection has been secured, the client will send an authentication request to the [SSHHost](#sshhost-property-sshreversetunnel-component) containing the [SSHUser](#sshuser-property-sshreversetunnel-component). The server will respond containing a list of methods by which that user may be authenticated.

The component will attempt to authenticate the user by one of those methods based on the value of SSHAuthMode and other property values supplied by the user. Currently, the component supports the following authentication methods:

|  |  |
| --- | --- |
| amNone (0) | No authentication will be performed. The current [SSHUser](#sshuser-property-sshreversetunnel-component) value is ignored, and the connection will be logged as anonymous. |
| amMultiFactor (1) | This allows the component to attempt a multistep authentication process. The component will send authentication data to the server based on the list of methods allowed for the current user and the authentication property values supplied. The component will continue to send authentication data until the server acknowledges authentication success. If the server rejects an authentication step, the component throws an exception. |
| amPassword (2) | The component will use the values of [SSHUser](#sshuser-property-sshreversetunnel-component) and [SSHPassword](#sshpassword-property-sshreversetunnel-component) to authenticate the user. |
| amPublicKey (3) | The component will use the values of [SSHUser](#sshuser-property-sshreversetunnel-component) and [SSHCert](#sshcert-property-sshreversetunnel-component) to authenticate the user. [SSHCert](#sshcert-property-sshreversetunnel-component) must have a private key available for this authentication method to succeed. |
| amKeyboardInteractive (4) | At the time of authentication, the component will fire the [SSHKeyboardInteractive](#sshkeyboardinteractive-event-sshreversetunnel-component) event containing instructions on how to complete the authentication step. NOTE: amKeyboardInteractive is not supported in SSHTunnel. |
| amGSSAPIWithMic (5) | This allows the component to attempt Kerberos authentication using the GSSAPI-WITH-MIC scheme. The client will try Kerberos authentication using the value of [SSHUser](#sshuser-property-sshreversetunnel-component) (single sign-on), or if [SSHPassword](#sshpassword-property-sshreversetunnel-component) is specified as well, it will try Kerberos authentication with alternate credentials. This is currently supported only on Windows, unless using the Java edition, which also provides support for Linux and macOS. |
| amGSSAPIKeyex (6) | This allows the component to attempt Kerberos authentication using the GSSAPIKeyex scheme. The client will try Kerberos authentication using the value of [SSHUser](#sshuser-property-sshreversetunnel-component) (single sign-on), or if [SSHPassword](#sshpassword-property-sshreversetunnel-component) is specified as well, it will try Kerberos authentication with alternate credentials. This is currently supported only on Windows, unless using the Java edition, which also provides support for Linux and macOS. |
| amCustom (99) | This allows the component caller to take over the authentication process completely. When amCustom is set, the component will fire the [SSHCustomAuth](#sshcustomauth-event-sshreversetunnel-component) event as necessary to complete the authentication process. |

**Example 1. User/Password Authentication:**

```text
Control.SSHAuthMode = SftpSSHAuthModes.amPassword
Control.SSHUser = "username"
Control.SSHPassword = "password"
Control.SSHLogon("server", 22)
```

 **Example 2. Public Key Authentication:**

```text
Control.SSHAuthMode = SftpSSHAuthModes.amPublicKey
Control.SSHUser = "username"

Control.SSHCert = New Certificate(CertStoreTypes.cstPFXFile, "cert.pfx", "certpassword", "*")
Control.SSHLogon("server", 22)
```

# SSHCert Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

A certificate to be used for authenticating the [SSHUser](#sshuser-property-sshreversetunnel-component) .

## Syntax

```text
public Certificate SSHCert { get; set; }
```

## Remarks

To use public key authentication, SSHCert must contain a [Certificate](#certificate-type) with a valid private key. The certificate's public key value is sent to the server along with a signature produced using the private key. The server will first check to see if the public key values match what is known for the user, and then it will attempt to use those values to verify the signature.

**Example 1. User/Password Authentication:**

```text
Control.SSHAuthMode = SftpSSHAuthModes.amPassword
Control.SSHUser = "username"
Control.SSHPassword = "password"
Control.SSHLogon("server", 22)
```

 **Example 2. Public Key Authentication:**

```text
Control.SSHAuthMode = SftpSSHAuthModes.amPublicKey
Control.SSHUser = "username"

Control.SSHCert = New Certificate(CertStoreTypes.cstPFXFile, "cert.pfx", "certpassword", "*")
Control.SSHLogon("server", 22)
```

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

# SSHCompressionAlgorithms Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The comma-separated list containing all allowable compression algorithms.

## Syntax

```text
public string SSHCompressionAlgorithms { get; set; }
```

## 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 component 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 component:

- zlib
- zlib@openssh.com
- none

# SSHEncryptionAlgorithms Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The comma-separated list containing all allowable encryption algorithms.

## Syntax

```text
public string SSHEncryptionAlgorithms { get; set; }
```

## 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 component 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 component:

- 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

# SSHHost Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The address of the Secure Shell (SSH) host.

## Syntax

```text
public string SSHHost { get; set; }
```

## Default Value

""

## Remarks

The SSHHost property specifies the IP address (IP number in dotted internet format) or domain name of the remote host. It is set before a connection is attempted and cannot be changed once a connection is established.

If the SSHHost property is set to a domain name, a DNS request is initiated, and upon successful termination of the request, the SSHHost property is set to the corresponding address. If the search is not successful, an error is returned.

The SSHHost must be the same host that will be assumed for SSH as for the remote service being connected to.

# SSHPassword Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The password for Secure Shell (SSH) password-based authentication.

## Syntax

```text
public string SSHPassword { get; set; }
```

## Default Value

""

## Remarks

SSHPassword specifies the password that is used to authenticate the client to the SSH server.

# SSHPort Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The port on the Secure Shell (SSH) server where the SSH service is running; by default, 22.

## Syntax

```text
public int SSHPort { get; set; }
```

## Default Value

22

## Remarks

The SSHPort specifies a service port on the SSH host to connect to.

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change this property while connected will fail with an error.

# SSHUser Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

The username for Secure Shell (SSH) authentication.

## Syntax

```text
public string SSHUser { get; set; }
```

## Default Value

""

## Remarks

SSHUser specifies the username that is used to authenticate the client to the SSH server. This property is required.

**Example 1. User/Password Authentication:**

```text
Control.SSHAuthMode = SftpSSHAuthModes.amPassword
Control.SSHUser = "username"
Control.SSHPassword = "password"
Control.SSHLogon("server", 22)
```

 **Example 2. Public Key Authentication:**

```text
Control.SSHAuthMode = SftpSSHAuthModes.amPublicKey
Control.SSHUser = "username"

Control.SSHCert = New Certificate(CertStoreTypes.cstPFXFile, "cert.pfx", "certpassword", "*")
Control.SSHLogon("server", 22)
```

# Timeout Property ([SSHReverseTunnel](#sshreversetunnel-component) Component)

This property includes the timeout for the component.

## Syntax

```text
public int Timeout { get; set; }
```

## Default Value

60

## Remarks

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

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

The component will use [DoEvents](#doevents-method-sshreversetunnel-component) 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 component 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 Timeout property is 60 seconds.

# CancelForwarding Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Requests the server to stop forwarding a remote Transmission Control Protocol (TCP)/IP port.

## Syntax

```text
public void CancelForwarding(string address, int port);

Async Version
public async Task CancelForwarding(string address, int port);
public async Task CancelForwarding(string address, int port, CancellationToken cancellationToken);
```

## Remarks

The CancelForwarding cancels a previous TCP/IP port forwarding request. When calling it, provide the same argument values you provided on the [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) call.

# CloseChannel Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Closes an existing SSHChannel .

## Syntax

```text
public void CloseChannel(string channelId);

Async Version
public async Task CloseChannel(string channelId);
public async Task CloseChannel(string channelId, CancellationToken cancellationToken);
```

## Remarks

*ChannelId* is the identifier for the Secure Shell (SSH) channel to be closed.

# Config Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Sets or retrieves a configuration setting.

## Syntax

```text
public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);
```

## Remarks

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

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, 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-sshreversetunnel-component), you must call *Config("PROPERTY")*. The value will be returned as a string.

# DecodePacket Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Decodes a hex-encoded Secure Shell (SSH) packet

## Syntax

```text
public byte[] DecodePacket(string encodedPacket);

Async Version
public async Task<byte[]> DecodePacket(string encodedPacket);
public async Task<byte[]> DecodePacket(string encodedPacket, CancellationToken cancellationToken);
```

## Remarks

This method is used to decode an SSH packet created by [EncodePacket](#encodepacket-method-sshreversetunnel-component).

NOTE: This method is applicable only for reading and creating Secure Shell (SSH) packets for use within the [SSHCustomAuth](#sshcustomauth-event-sshreversetunnel-component) event.

# DoEvents Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

This method processes events from the internal message queue.

## Syntax

```text
public void DoEvents();

Async Version
public async Task DoEvents();
public async Task DoEvents(CancellationToken cancellationToken);
```

## Remarks

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

# EncodePacket Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Hex encodes a Secure Shell (SSH) packet.

## Syntax

```text
public string EncodePacket(byte[] packet);

Async Version
public async Task<string> EncodePacket(byte[] packet);
public async Task<string> EncodePacket(byte[] packet, CancellationToken cancellationToken);
```

## Remarks

This method is used to encode a raw SSH packet created by [SetSSHParam](#setsshparam-method-sshreversetunnel-component).

NOTE: This method is applicable only for reading and creating Secure Shell (SSH) packets for use within the [SSHCustomAuth](#sshcustomauth-event-sshreversetunnel-component) event.

# ExchangeKeys Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Causes the component to exchange a new set of session keys with the [SSHHost](#sshhost-property-sshreversetunnel-component) .

## Syntax

```text
public void ExchangeKeys();

Async Version
public async Task ExchangeKeys();
public async Task ExchangeKeys(CancellationToken cancellationToken);
```

## Remarks

Secure Shell (SSH) key renegotiation can be initiated by either end of an established SSH connection. ExchangeKeys allows the user to start such a renegotiation with the [SSHHost](#sshhost-property-sshreversetunnel-component). During this process, [SSHStatus](#sshstatus-event-sshreversetunnel-component) events will fire containing updates regarding 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. Doing so makes it more difficult to break the security of data-intensive or long-lived connections.

# GetSSHParam Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Reads a field from a Secure Shell (SSH) packet's payload.

## Syntax

```text
public string GetSSHParam(byte[] payload, string field);

Async Version
public async Task<string> GetSSHParam(byte[] payload, string field);
public async Task<string> GetSSHParam(byte[] payload, string field, CancellationToken cancellationToken);
```

## Remarks

This method is used to read the value of a particular field from an SSH packet's payload. *Payload* should contain the full payload of a packet received by an event such as [SSHChannelRequest](#sshchannelrequest-event-sshreversetunnel-component). *Field* is the name of a field to be read out of the packet.

The following is a list of the names of well-known channel request field names and their encodings:

|  |  |
| --- | --- |
| ChannelId (int32) | The Id of the channel that received the packet. |
| RequestType (string) | The type of channel requested. |
| WantsReply (boolean) | Whether or not the client wants a reply to the request. |

The remaining fields that are available in the payload are dependent on the value of *RequestType*.

**pty-req**

Pty-req is a request to open a pseudo terminal on the specified channel. The following fields are available:

|  |  |
| --- | --- |
| TerminalType (string) | The type of terminal being requested (e.g., "vt100"). |
| TerminalWidthCharacters (int32) | The width, in characters, of the terminal to be opened. |
| TerminalHeightRows (int32) | The height, in rows, of the terminal to be opened. |
| TerminalWidthPixels (int32) | The width, in pixels, of the terminal to be opened. |
| TerminalHeightPixels (int32) | The height, in pixels, of the terminal to be opened. |
| TerminalModes (string) | A list of op-val (int32-byte) encoded modes to be used by the terminal. |

**x11-req**

X11-req is a request to forward x11 sessions over a channel. The following fields are available:

|  |  |
| --- | --- |
| SingleConnection (boolean) | Disallows more than one connection to be forwarded by the channel. |
| X11AuthProtocol (string) | The authentication protocol to be used (e.g., "MIT-MAGIC-COOKIE-1"). |
| X11AuthCookie (string) | A hexadecimal-encoded cookie to be used for authentication. |
| X11ScreenNumber (int32) | The x11 screen number to be used. |

**env**

Env is a request to set an environment variable to be passed into a shell that may be started later. The following fields are available:

|  |  |
| --- | --- |
| VariableName (string) | The name of the variable to be set. |
| VariableValue (string) | The value of the variable to be set. |

**exec**

Exec is a request to execute a command on the channel using the authenticated user's shell. The following field is available:

|  |  |
| --- | --- |
| Command (string) | The command to be executed. |

**subsystem**

Subsystem is a request to start a subsystem on the specified channel. The following field is available:

|  |  |
| --- | --- |
| Subsystem (string) | The name of the subsystem to be started (e.g., "sftp"). |

**xon-xoff**

Xon-xoff instructs the server to allow or disallow control-S/control-Q style flow control. The following field is available:

|  |  |
| --- | --- |
| ClientCanDo (boolean) | Whether or not the server should enable flow control. |

**signal**

Sends a signal to the remote process/service. The following field is available:

|  |  |
| --- | --- |
| SignalName (string) | The name of the signal to be sent. |

If the packet type is not well known, *Field* should start with the special character "%" and contain a comma-separated list of field types as defined in [SetSSHParam](#setsshparam-method-sshreversetunnel-component). For example, reading out the X11AuthProtocol of an x11-req payload, you can use "%s,f".

NOTE: The return value is a string encoded the same way as the *FieldValue* param in [SetSSHParam](#setsshparam-method-sshreversetunnel-component).

NOTE: This method is applicable only for reading and creating Secure Shell (SSH) packets for use within the [SSHCustomAuth](#sshcustomauth-event-sshreversetunnel-component) event.

# GetSSHParamBytes Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Reads a field from a Secure Shell (SSH) packet's payload.

## Syntax

```text
public byte[] GetSSHParamBytes(byte[] payload, string field);

Async Version
public async Task<byte[]> GetSSHParamBytes(byte[] payload, string field);
public async Task<byte[]> GetSSHParamBytes(byte[] payload, string field, CancellationToken cancellationToken);
```

## Remarks

This method is the same as calling [GetSSHParam](#getsshparam-method-sshreversetunnel-component), but it returns raw bytes instead of strings.

NOTE: This method is applicable only for reading and creating Secure Shell (SSH) packets for use within the [SSHCustomAuth](#sshcustomauth-event-sshreversetunnel-component) event.

# Interrupt Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

This method interrupts the current method.

## Syntax

```text
public void Interrupt();

Async Version
public async Task Interrupt();
public async Task Interrupt(CancellationToken cancellationToken);
```

## Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

# RequestForwarding Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Requests the server to forward a remote Transmission Control Protocol (TCP)/IP port.

## Syntax

```text
public void RequestForwarding(string address, int port, string forwardingHost, int forwardingPort);

Async Version
public async Task RequestForwarding(string address, int port, string forwardingHost, int forwardingPort);
public async Task RequestForwarding(string address, int port, string forwardingHost, int forwardingPort, CancellationToken cancellationToken);
```

## Remarks

The RequestForwarding method asks the server to listen at the specified TCP/IP *Address* and *Port* for connection requests and then forward them as new Secure Shell (SSH) channels to the component.

*ForwardingHost* and *ForwardingPort* may be used to specify an address and port to which traffic will automatically be forwarded. If automatic forwarding is not desired, specify an empty string ("") for the *ForwardingHost* parameter.

The *Address* argument can be specified in different ways:

-  "" means that connections are to be accepted on all protocol families supported by the server.
-  "0.0.0.0" means to listen on all IPv4 addresses.
-  "::" means to listen on all IPv6 addresses.
-  "localhost" means to listen on all protocol families supported by the Secure Shell (SSH) implementation on loopback addresses only.
-  "127.0.0.1" and "::1" indicate listening on the loopback interfaces for IPv4 and IPv6, respectively.

Passing a value of 0 for the *Port* parameter instructs the server to assign a port. In this case, query the [ForwardedPort](#ForwardedPort) setting to determine the port that was assigned by the server.

The component has two modes that allow data to be dealt with directly from the events, or automatically forwarded on to a different endpoint.

**Event Based Operation**

In this mode, any data received by the component over the tunnel causes the events of the component to fire. For instance:

```text
SSHReverseTunnel.RequestForwarding("0.0.0.0", 777, "", 0);
```

In the above code, forwarding is requested from port 777 on the [SSHHost](#sshhost-property-sshreversetunnel-component). Any data received on port 777 by the [SSHHost](#sshhost-property-sshreversetunnel-component) will be sent to the component. In the above code, the last two parameters are empty and 0, indicating to the component that no local forwarding is requested.

Once RequestForwarding returns, the Secure Shell (SSH) reverse tunnel is established. Any connection made to the SSH host on the specified port will then trigger the component's events to fire, allowing you to handle the connection request and data.

When a client connects to the SSH host on the specified port, the [SSHChannelOpenRequest](#sshchannelopenrequest-event-sshreversetunnel-component) event will fire. Within this event, choose to accept or reject the connection by setting the *Accept* parameter. This event contains details about the connection that may be used when determining whether to accept the connection.

After the channel is established, data are received through the [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) event. Call the [SendChannelData](#sendchanneldata-method-sshreversetunnel-component) method to send data over the channel, and call the [CloseChannel](#closechannel-method-sshreversetunnel-component) method to close the channel.

**Local Forwarding**

In this mode, any data received by the component is automatically forwarded to a separate endpoint. This allows the component to act as a sort of proxy. There is no need to handle data directly in this case. For instance:

```text
SSHReverseTunnel.RequestForwarding("0.0.0.0", 777, "nsoftware.com", 80);
```

In the above code, forwarding is requested from port 777 on [SSHHost](#sshhost-property-sshreversetunnel-component). The component is instructed to establish a connection to "nsoftware.com" on port 80 when a client connects to [SSHHost](#sshhost-property-sshreversetunnel-component) on port 777. Any data received from the client connected to [SSHHost](#sshhost-property-sshreversetunnel-component) on port 777 will automatically be forwarded to "nsoftware.com" on port 80. Any data received back from "nsoftware.com" on port 80 will be sent back to the connected client.

In this mode, data may flow freely from the client connected to the [SSHHost](#sshhost-property-sshreversetunnel-component) to the endpoint specified in the RequestForwarding method without any additional code required.

# Reset Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

This method will reset the component.

## Syntax

```text
public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);
```

## Remarks

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

# SendChannelData Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Sends data over a Secure Shell (SSH) channel.

## Syntax

```text
public void SendChannelData(string channelId, byte[] data);

Async Version
public async Task SendChannelData(string channelId, byte[] data);
public async Task SendChannelData(string channelId, byte[] data, CancellationToken cancellationToken);
```

## Remarks

This method can be used to send arbitrary data to the channel with the specified *ChannelId*.

# SetSSHParam Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Writes a field to the end of a payload.

## Syntax

```text
public byte[] SetSSHParam(byte[] payload, string fieldType, string fieldValue);

Async Version
public async Task<byte[]> SetSSHParam(byte[] payload, string fieldType, string fieldValue);
public async Task<byte[]> SetSSHParam(byte[] payload, string fieldType, string fieldValue, CancellationToken cancellationToken);
```

## Remarks

This method is used to build the payload portion of a Secure Shell (SSH) packet to be sent later by a call to SendSSHPacket. *Payload* should contain the result of a previous call to SetSSHParam. *FieldType* is a string defining the type of field to be written to the packet. *FieldValue* should be the string representation of the field to be written.

The following is a list of supported field types and a description of how *FieldValue* should be encoded:

|  |  |
| --- | --- |
| s | A plaintext string containing the default system encoding of the data. |
| sb | A string containing the hex-encoded data (e.g., "A1B23C") |
| m | A variable-length large integer, encoded as a textual representation of the value (e.g., "1234"). |
| i | A 32-bit integer, encoded as a textual representation of the value (e.g., "1234"). |
| l | A 64-bit integer, encoded as a textual representation of the value (e.g., "1234"). |
| b | A single byte, encoded as a textual representation of the value (e.g., "123"). |
| f | A boolean flag, encoded as a textual representation of the value (e.g., 'True' or 'False') |

NOTE: Integer values may be hexadecimal encoded by prefixing "0x" to the beginning of the string; otherwise, the value is assumed to be Base10.

NOTE: This method is applicable only for reading and creating Secure Shell (SSH) packets for use within the [SSHCustomAuth](#sshcustomauth-event-sshreversetunnel-component) event.

# SSHLogoff Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Logs off from the Secure Shell (SSH) server.

## Syntax

```text
public void SSHLogoff();

Async Version
public async Task SSHLogoff();
public async Task SSHLogoff(CancellationToken cancellationToken);
```

## Remarks

Logs off from the SSH server. If that fails, the connection is terminated by the local host.

# SSHLogon Method ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Logs on to the [SSHHost](#sshhost-property-sshreversetunnel-component) using the current [SSHUser](#sshuser-property-sshreversetunnel-component) and [SSHPassword](#sshpassword-property-sshreversetunnel-component) .

## Syntax

```text
public void SSHLogon(string SSHHost, int SSHPort);

Async Version
public async Task SSHLogon(string SSHHost, int SSHPort);
public async Task SSHLogon(string SSHHost, int SSHPort, CancellationToken cancellationToken);
```

## Remarks

Logs on to the Secure Shell (SSH) server using the current [SSHUser](#sshuser-property-sshreversetunnel-component) and [SSHPassword](#sshpassword-property-sshreversetunnel-component). This will perform the SSH handshake and authentication.

**Example. Logging On:**

```text
SSHClient.SSHUser = "username"
SSHClient.SSHPassword = "password"
SSHClient.SSHLogon("sshHost", sshPort)
```

# Connected Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired immediately after a connection completes (or fails).

## Syntax

```text
public event OnConnectedHandler OnConnected;

public delegate void OnConnectedHandler(object sender, SSHReverseTunnelConnectedEventArgs e);

public class SSHReverseTunnelConnectedEventArgs : EventArgs {
  public int StatusCode { get; }
  public string Description { get; }
}
```

## 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 Transmission Control Protocol (TCP)/IP stack. *Description* contains a description of this code. The value of *StatusCode* is equal to the value of the error.

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

# ConnectionStatus Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired to indicate changes in the connection state.

## Syntax

```text
public event OnConnectionStatusHandler OnConnectionStatus;

public delegate void OnConnectionStatusHandler(object sender, SSHReverseTunnelConnectionStatusEventArgs e);

public class SSHReverseTunnelConnectionStatusEventArgs : EventArgs {
  public string ConnectionEvent { get; }
  public int StatusCode { get; }
  public string Description { get; }
}
```

## Remarks

This event is fired when the connection state changes: for example, completion of a firewall or proxy connection or completion of a security handshake.

The *ConnectionEvent* parameter indicates the type of connection event. Values may include the following:

|  |  |
| --- | --- |
|  | Firewall connection complete. |
|  | Secure Sockets Layer (SSL) or S/Shell handshake complete (where applicable). |
|  | Remote host connection complete. |
|  | Remote host disconnected. |
|  | SSL or S/Shell connection broken. |
|  | Firewall host disconnected. |

 *StatusCode* has the error code returned by the Transmission Control Protocol (TCP)/IP stack. *Description* contains a description of this code. The value of *StatusCode* is equal to the value of the error.

# Disconnected Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when a connection is closed.

## Syntax

```text
public event OnDisconnectedHandler OnDisconnected;

public delegate void OnDisconnectedHandler(object sender, SSHReverseTunnelDisconnectedEventArgs e);

public class SSHReverseTunnelDisconnectedEventArgs : EventArgs {
  public int StatusCode { get; }
  public string Description { get; }
}
```

## 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 Transmission Control Protocol (TCP/IP) subsystem. *Description* contains a description of this code. The value of *StatusCode* is equal to the value of the TCP/IP error.

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

# Error Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when information is available about errors during data delivery.

## Syntax

```text
public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, SSHReverseTunnelErrorEventArgs e);

public class SSHReverseTunnelErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}
```

## Remarks

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

The *ErrorCode* parameter contains an error code, and the *Description* parameter 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-sshreversetunnel-component) section.

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

The *ErrorCode* parameter contains an error code, and the *Description* parameter 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-sshreversetunnel-component) section.

# Log Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired once for each log message.

## Syntax

```text
public event OnLogHandler OnLog;

public delegate void OnLogHandler(object sender, SSHReverseTunnelLogEventArgs e);

public class SSHReverseTunnelLogEventArgs : EventArgs {
  public int LogLevel { get; }
  public string Message { get; }
  public string LogType { get; }
}
```

## Remarks

Fired once for each log message generated by the component. 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.

# ReconnectAttempt Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when attempting to reconnect.

## Syntax

```text
public event OnReconnectAttemptHandler OnReconnectAttempt;

public delegate void OnReconnectAttemptHandler(object sender, SSHReverseTunnelReconnectAttemptEventArgs e);

public class SSHReverseTunnelReconnectAttemptEventArgs : EventArgs {
  public string Host { get; }
  public int Port { get; }
  public int RetryCount { get; }
  public int RetriesRemaining { get; }
  public int MaxRetryCount { get; }
  public int RetryInterval { get; }
  public int RetryType { get; }
  public int RemoteListeningPort { get; }
  public bool Cancel { get; set; }
}
```

## Remarks

This event fires both when attempting to reconnect to the [SSHHost](#sshhost-property-sshreversetunnel-component) and when reestablishing a Secure Shell (SSH) tunnel.

This is applicable only when [AutoReconnect](#AutoReconnect) is enabled. To determine which type of connection is being established check the *RetryType* parameter.

The following table provides details about the parameters:

|  |  |
| --- | --- |
| Host | The SSH host to which the connection is attempted. |
| Port | The port on the SSH host to which the connection is attempted. |
| RetryCount | The current retry attempt. For instance, this may be attempt number 2 out of 5, then RetryCount will hold the value 2. |
| RetriesRemaining | The number of retries remaining after this attempt. This number does not include the current attempt. If [MaxRetryCount](#MaxRetryCount) is set to unlimited, this will return -1. |
| MaxRetryCount | The maximum number of retries as specified in [MaxRetryCount](#MaxRetryCount). |
| RetryInterval | The interval (in seconds) between retry attempts as specified in [RetryInterval](#RetryInterval). |
| RetryType | The type of connection being retried. Possible values are as follows: 0 - SSH 1 - Tunnel |
| RemoteListeningPort | The port on the SSH host that the reverse tunnel will use. This is applicable only when RetryType is 1. |
| Cancel | Maybe set within this event to cancel the retry attempts. If set to True, no further retry attempts will be executed. |

# SSHChannelClosed Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when a channel is closed.

## Syntax

```text
public event OnSSHChannelClosedHandler OnSSHChannelClosed;

public delegate void OnSSHChannelClosedHandler(object sender, SSHReverseTunnelSSHChannelClosedEventArgs e);

public class SSHReverseTunnelSSHChannelClosedEventArgs : EventArgs {
  public string ChannelId { get; }
}
```

## Remarks

The SSHChannelClosed event is fired when a channel is closed on a Secure Shell (SSH) connection.

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.

# SSHChannelData Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when the [SSHHost](#sshhost-property-sshreversetunnel-component) sends channel data to the client.

## Syntax

```text
public event OnSSHChannelDataHandler OnSSHChannelData;

public delegate void OnSSHChannelDataHandler(object sender, SSHReverseTunnelSSHChannelDataEventArgs e);

public class SSHReverseTunnelSSHChannelDataEventArgs : EventArgs {
  public string ChannelId { get; }
  public string ChannelData { get; }  public byte[] ChannelDataB { get; }
  public bool ChannelDataEOLFound { get; }
}
```

## Remarks

The SSHChannelData event will fire as data are received for the given *ChannelId*. *ChannelData* will contain the decrypted contents of the Secure Shell (SSH) packet.

*ChannelDataEOLFound* indicates whether or not the *ChannelEOL* string for the channel was found at the end of *ChannelData*. If the *ChannelEOL* string was found, then *ChannelDataEOLFound* is True.

If *ChannelData* is part of a data portion of a length that is larger than the *MaxChannelLength* for the Channel with no *ChannelEOL* strings in it, then *ChannelDataEOLFound* is False.

NOTE: This means that one of more SSHChannelData events with *ChannelDataEOLFound* set to False can be received.

If the *ChannelEOL* property for the Channel is "" (empty string), then *ChannelDataEOLFound* can be disregarded (it is always True).

# SSHChannelEOF Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when the remote peer signals the end of the data stream for the channel.

## Syntax

```text
public event OnSSHChannelEOFHandler OnSSHChannelEOF;

public delegate void OnSSHChannelEOFHandler(object sender, SSHReverseTunnelSSHChannelEOFEventArgs e);

public class SSHReverseTunnelSSHChannelEOFEventArgs : EventArgs {
  public string ChannelId { get; }
}
```

## Remarks

The SSHChannelEOF event is fired when the end of the data stream for a channel on a Secure Shell (SSH) connection is reached.

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.

# SSHChannelOpened Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when a channel is successfully opened.

## Syntax

```text
public event OnSSHChannelOpenedHandler OnSSHChannelOpened;

public delegate void OnSSHChannelOpenedHandler(object sender, SSHReverseTunnelSSHChannelOpenedEventArgs e);

public class SSHReverseTunnelSSHChannelOpenedEventArgs : EventArgs {
  public string ChannelId { get; }
}
```

## Remarks

The SSHChannelOpened event is fired when a channel is successfully opened on a Secure Shell (SSH) connection.

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.

# SSHChannelOpenRequest Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when the peer attempts to open a new channel.

## Syntax

```text
public event OnSSHChannelOpenRequestHandler OnSSHChannelOpenRequest;

public delegate void OnSSHChannelOpenRequestHandler(object sender, SSHReverseTunnelSSHChannelOpenRequestEventArgs e);

public class SSHReverseTunnelSSHChannelOpenRequestEventArgs : EventArgs {
  public string ChannelId { get; }
  public string Service { get; }
  public string ConnectedAddress { get; }
  public int ConnectedPort { get; }
  public string OriginAddress { get; }
  public int OriginPort { get; }
  public bool Accept { get; set; }
}
```

## Remarks

This event is fired whenever a peer attempts to open a new channel for a given connection. *ChannelId* will contain the Id of the channel to be created. *Service* will identify the type of channel that is being requested. Usually, this will be "forwarded-tcpip", in which case *ConnectedAddress* and *ConnectedPort* will contain the remote Transmission Control Protocol (TCP)/IP address and port on the peer to which the connection was established; *OriginAddress* and *OriginPort* contain the originating TCP/IP address and port of the connection.

By default, *Accept* is True and the channel will be opened. Set *Accept* to False to reject the request.

# SSHChannelReadyToSend Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when the component is ready to send data.

## Syntax

```text
public event OnSSHChannelReadyToSendHandler OnSSHChannelReadyToSend;

public delegate void OnSSHChannelReadyToSendHandler(object sender, SSHReverseTunnelSSHChannelReadyToSendEventArgs e);

public class SSHReverseTunnelSSHChannelReadyToSendEventArgs : EventArgs {
  public string ChannelId { get; }
}
```

## Remarks

This event fires when data can be sent over the Secure Shell (SSH) Channel specified by *ChannelId*.

When a channel is opened, this event will fire after the channel is ready and data can be sent.

When [Timeout](#timeout-property-sshreversetunnel-component) is set to *0* (asynchronous) sending data may result in an error if the channel or underlying socket cannot accept more data to send. Monitor SSHChannelReadyToSend or ReadyToSend to determine when data can be sent again.

When [Timeout](#timeout-property-sshreversetunnel-component) is set to a positive value, the component will block when sending data until the data can be successfully sent and SSHChannelReadyToSend and ReadyToSend do not need to be monitored.

# SSHChannelRequest Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when the [SSHHost](#sshhost-property-sshreversetunnel-component) sends a channel request to the client.

## Syntax

```text
public event OnSSHChannelRequestHandler OnSSHChannelRequest;

public delegate void OnSSHChannelRequestHandler(object sender, SSHReverseTunnelSSHChannelRequestEventArgs e);

public class SSHReverseTunnelSSHChannelRequestEventArgs : EventArgs {
  public string ChannelId { get; }
  public string RequestType { get; }
  public string Packet { get; }  public byte[] PacketB { get; }
  public bool Success { get; set; }
}
```

## Remarks

The [SSHHost](#sshhost-property-sshreversetunnel-component) may send requests that affect the status of a particular [SSHChannel](#Type_SSHChannel). Some requests will be automatically handled by the component. Others, however, may need the attention of the user to be dealt with properly within the scope of the application.

*ChannelId* identifies the channel receiving the request.

*Type* will contain the type of the request. These types depend on the type of the channel. For example, a "session" channel executing a command on the remote shell may receive an "exit-status" request containing the return code of that command.

*RequestData* contains the remainder of the original Secure Shell (SSH) packet. If the request type has specific parameters, they can be parsed out of this data.

*Success* should be used to instruct the component to respond to the request with either a success or failure notification. If the request is successful, [SSHChannelRequested](#sshchannelrequested-event-sshreversetunnel-component) will fire with the same information in case the request requires further processing.

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.

# SSHChannelRequested Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired if the SSHChannelRequest was successful; any further processing for the channel request should be done here.

## Syntax

```text
public event OnSSHChannelRequestedHandler OnSSHChannelRequested;

public delegate void OnSSHChannelRequestedHandler(object sender, SSHReverseTunnelSSHChannelRequestedEventArgs e);

public class SSHReverseTunnelSSHChannelRequestedEventArgs : EventArgs {
  public string ChannelId { get; }
  public string RequestType { get; }
  public string Packet { get; }  public byte[] PacketB { get; }
}
```

## Remarks

The [SSHHost](#sshhost-property-sshreversetunnel-component) may send requests that affect the status of a particular [SSHChannel](#Type_SSHChannel). Some requests will be automatically handled by the component. Others, however, may need the attention of the user to be dealt with properly within the scope of the application.

*ChannelId* identifies the channel receiving the request.

*Type* will contain the type of the request. These types depend on the type of the channel. For example, a "session" channel executing a command on the remote shell may receive an "exit-status" request containing the return code of that command.

*RequestData* contains the remainder of the original Secure Shell (SSH) packet. If the request type has specific parameters, they can be parsed out of this data.

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.

# SSHCustomAuth Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when the component is doing a custom authentication.

## Syntax

```text
public event OnSSHCustomAuthHandler OnSSHCustomAuth;

public delegate void OnSSHCustomAuthHandler(object sender, SSHReverseTunnelSSHCustomAuthEventArgs e);

public class SSHReverseTunnelSSHCustomAuthEventArgs : EventArgs {
  public string Packet { get; set; }
}
```

## Remarks

SSHCustomAuth is fired during the user authentication stage of the Secure Shell (SSH) logon process if [SSHAuthMode](#sshauthmode-property-sshreversetunnel-component) is set to amCustom. *Packet* contains the last raw SSH packet sent by the server, in HEX-encoded format.

The client should create a new raw SSH packet to send to the server and set *Packet* to the HEX-encoded representation of the packet to send.

In all cases, *Packet* will start with the message type field.

To read the incoming packet, call [DecodePacket](#decodepacket-method-sshreversetunnel-component) and then use the [GetSSHParam](#getsshparam-method-sshreversetunnel-component) and [GetSSHParamBytes](#getsshparambytes-method-sshreversetunnel-component) methods. To create a packet, use the [SetSSHParam](#setsshparam-method-sshreversetunnel-component) method and then call [EncodePacket](#encodepacket-method-sshreversetunnel-component) to obtain a HEX-encoded value and assign this to the *Packet* parameter.

# SSHKeyboardInteractive Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired when the component receives a request for user input from the server.

## Syntax

```text
public event OnSSHKeyboardInteractiveHandler OnSSHKeyboardInteractive;

public delegate void OnSSHKeyboardInteractiveHandler(object sender, SSHReverseTunnelSSHKeyboardInteractiveEventArgs e);

public class SSHReverseTunnelSSHKeyboardInteractiveEventArgs : EventArgs {
  public string Name { get; }
  public string Instructions { get; }
  public string Prompt { get; }
  public string Response { get; set; }
  public bool EchoResponse { get; }
}
```

## Remarks

SSHKeyboardInteractive is fired during the user authentication stage of the Secure Shell (SSH) logon process. During authentication, the component will request a list of available authentication methods for the [SSHUser](#sshuser-property-sshreversetunnel-component). For example, if the [SSHHost](#sshhost-property-sshreversetunnel-component) responds with "keyboard-interactive", the component will fire this event to allow the client application to set the password.

During authentication, the SSH server may respond with a request for the user's authentication information. *Name* is a server-provided value associated with the authentication method such as "CRYPTOCard Authentication". *Instructions* will contain specific instructions, also supplied by the server, for how the user should respond.

Along with these values, the server will also send at least one input *Prompt* to be displayed to and filled out by the user. *Response* should be set to the user's input, and will be sent back in the user authentication information response. *EchoResponse* is a server recommendation for whether or not the user's response should be echoed back during input.

NOTE: The server may send several prompts in a single packet. The component will fire the SSHKeyboardInteractive event once for each prompt.

# SSHServerAuthentication Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired after the server presents its public key to the client.

## Syntax

```text
public event OnSSHServerAuthenticationHandler OnSSHServerAuthentication;

public delegate void OnSSHServerAuthenticationHandler(object sender, SSHReverseTunnelSSHServerAuthenticationEventArgs e);

public class SSHReverseTunnelSSHServerAuthenticationEventArgs : EventArgs {
  public string HostKey { get; }  public byte[] HostKeyB { get; }
  public string Fingerprint { get; }
  public string KeyAlgorithm { get; }
  public string CertSubject { get; }
  public string CertIssuer { get; }
  public string Status { get; }
  public bool Accept { get; set; }
}
```

## Remarks

This event is fired when the client can decide whether or not to continue with the connection process. If the public key is known to be a valid key for the Secure Shell (SSH) server, *Accept* should be set to True within the event. Otherwise, the server will not be authenticated and the connection will be broken.

*Accept* will be True only if either *HostKey* or *Fingerprint* is identical to the value of [SSHAcceptServerHostKey](#sshacceptserverhostkey-property-sshreversetunnel-component).

Accept may be set to True manually to accept the server host key.

NOTE: SSH's security inherently relies on client verification of the host key. Ignoring the host key and always setting *Accept* to True is strongly discouraged, and could cause potentially serious security vulnerabilities in your application. It is recommended that clients maintain a list of known keys for each server and check *HostKey* against this list each time a connection is attempted.

**Host Key** contains the full binary text of the key, in the same format used internally by SSH.

*Fingerprint* holds the SHA-256 hash of *HostKey* in the hex-encoded form: *0a:1b:2c:3d*. To configure the hash algorithm used to calculate this value, see [SSHFingerprintHashAlgorithm](#SSHFingerprintHashAlgorithm). To configure the encoding format used when displaying this value, see [SSHFingerprintEncoding](#SSHFingerprintEncoding).

*KeyAlgorithm* identifies the host key algorithm. The following values are supported:

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

 To limit the accepted host key algorithms, refer to [SSHPublicKeyAlgorithms](#SSHPublicKeyAlgorithms).

*CertSubject* is the subject of the certificate. This is applicable only when *KeyAlgorithm* is "x509v3-sign-rsa" or "x509v3-sign-dss".

*CertIssuer* is the issuer of the certificate. This is applicable only when *KeyAlgorithm* is "x509v3-sign-rsa" or "x509v3-sign-dss".

*Status* is reserved for future use.

# SSHStatus Event ([SSHReverseTunnel](#sshreversetunnel-component) Component)

Fired to track the progress of the secure connection.

## Syntax

```text
public event OnSSHStatusHandler OnSSHStatus;

public delegate void OnSSHStatusHandler(object sender, SSHReverseTunnelSSHStatusEventArgs e);

public class SSHReverseTunnelSSHStatusEventArgs : EventArgs {
  public string Message { get; }
}
```

## Remarks

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

# 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)

- [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: ""

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: ""

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: ""

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

 **Fingerprint** *string (read-only)*
Default: ""

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: ""

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: ""

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: ""

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

 **PrivateKey** *string (read-only)*
Default: ""

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** *bool (read-only)*
Default: 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: ""

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: ""

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

 **PublicKeyAlgorithm** *string (read-only)*
Default: ""

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: 0

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

 **SerialNumber** *string (read-only)*
Default: ""

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: ""

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: "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. |

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: "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. |

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: ""

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

 **StoreType** *CertStoreTypes*
Default: 0

The type of certificate store for this certificate.

 The component supports both public and private keys in a variety of formats. When the *cstAuto* value is used, the component 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) component 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: ""

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

 **ThumbprintMD5** *string (read-only)*
Default: ""

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: ""

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: ""

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: ""

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: 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: ""

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

 **Subject** *string*
Default: ""

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: ""

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: ""

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(CertStoreTypes 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 component 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(CertStoreTypes 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 component 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(CertStoreTypes 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 component will load * Encoded * as an X.509 certificate and search the opened store for a corresponding private key.

```text
public Certificate(CertStoreTypes 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 component 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(CertStoreTypes 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 component 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(CertStoreTypes 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 component will load * Encoded * as an X.509 certificate and search the opened store for a corresponding private key.

# Firewall Type

The firewall the component will connect through.

## Remarks

When connecting through a firewall, this type is used to specify different properties of the firewall, such as the firewall [Host](#Firewall_f_Host) and the [FirewallType](#Firewall_f_FirewallType).

The following fields are available:

- [AutoDetect](#Firewall_f_AutoDetect)

- [FirewallType](#Firewall_f_FirewallType)

- [Host](#Firewall_f_Host)

- [Password](#Firewall_f_Password)

- [Port](#Firewall_f_Port)

- [User](#Firewall_f_User)

## Fields

 **AutoDetect** *bool*
Default: False

Whether to automatically detect and use firewall system settings, if available.

 **FirewallType** *FirewallTypes*
Default: 0

The type of firewall to connect through. The applicable values are as follows:

|  |  |
| --- | --- |
| fwNone (0) | No firewall (default setting). |
| fwTunnel (1) | Connect through a tunneling proxy. [Port](#Firewall_f_Port) is set to 80. |
| fwSOCKS4 (2) | Connect through a SOCKS4 Proxy. [Port](#Firewall_f_Port) is set to 1080. |
| fwSOCKS5 (3) | Connect through a SOCKS5 Proxy. [Port](#Firewall_f_Port) is set to 1080. |
| fwSOCKS4A (10) | Connect through a SOCKS4A Proxy. [Port](#Firewall_f_Port) is set to 1080. |

 **Host** *string*
Default: ""

The name or IP address of the firewall (optional). If a [Host](#Firewall_f_Host) is given, the requested connections will be authenticated through the specified firewall when connecting.

If this field is set to a Domain Name, a DNS request is initiated. Upon successful termination of the request, this field is set to the corresponding address. If the search is not successful, the component throws an exception.

 **Password** *string*
Default: ""

A password if authentication is to be used when connecting through the firewall. If [Host](#Firewall_f_Host) is specified, the [User](#Firewall_f_User) and [Password](#Firewall_f_Password) fields are used to connect and authenticate to the given firewall. If the authentication fails, the component throws an exception.

 **Port** *int*
Default: 0

The Transmission Control Protocol (TCP) port for the firewall [Host](#Firewall_f_Host). See the description of the [Host](#Firewall_f_Host) field for details.

NOTE: This field is set automatically when [FirewallType](#Firewall_f_FirewallType) is set to a valid value. See the description of the [FirewallType](#Firewall_f_FirewallType) field for details.

 **User** *string*
Default: ""

A username if authentication is to be used when connecting through a firewall. If [Host](#Firewall_f_Host) is specified, this field and the [Password](#Firewall_f_Password) field are used to connect and authenticate to the given [Firewall](#firewall-type). If the authentication fails, the component throws an exception.

## Constructors

```text
public Firewall();
```

# SSHRTChannel Type

A currently open Secure Shell (SSH) channel.

## Remarks

This type holds details about currently open channels. Each time a client connects to the reverse tunnel a new channel of this type is added to [Channels](#channels-property-sshreversetunnel-component).

The following fields are available:

- [BytesSent](#SSHRTChannel_f_BytesSent)

- [ChannelId](#SSHRTChannel_f_ChannelId)

- [ConnectedAddress](#SSHRTChannel_f_ConnectedAddress)

- [ConnectedPort](#SSHRTChannel_f_ConnectedPort)

- [ForwardingHost](#SSHRTChannel_f_ForwardingHost)

- [ForwardingPort](#SSHRTChannel_f_ForwardingPort)

- [OriginAddress](#SSHRTChannel_f_OriginAddress)

- [OriginPort](#SSHRTChannel_f_OriginPort)

- [Service](#SSHRTChannel_f_Service)

## Fields

 **BytesSent** *int (read-only)*
Default: 0

This field specifies the number of bytes actually sent after a sending channel data.

 **ChannelId** *string (read-only)*
Default: ""

This field provides an Id generated by the component to identify the current Secure Shell (SSH) channel.

This Id is unique to this channel.

 **ConnectedAddress** *string (read-only)*
Default: ""

This field holds the remote address to which the connection was established. This should match the *Address* parameter passed to the [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) method.

 **ConnectedPort** *int (read-only)*
Default: 0

This field holds the remote port to which the connection was established. This should match the *Port* parameter passed to the [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) method.

 **ForwardingHost** *string*
Default: ""

This field holds the host to which incoming traffic is forwarded. This is applicable only if local forwarding was requested when calling [RequestForwarding](#requestforwarding-method-sshreversetunnel-component).

 **ForwardingPort** *int*
Default: 0

This field holds the port to which incoming traffic is forwarded. This is applicable only if local forwarding was requested when calling [RequestForwarding](#requestforwarding-method-sshreversetunnel-component).

 **OriginAddress** *string (read-only)*
Default: ""

This field holds the address of the client that originated the connection to the reverse tunnel on [SSHHost](#sshhost-property-sshreversetunnel-component).

 **OriginPort** *int (read-only)*
Default: 0

This field holds the port used by the client that originated the connection to the reverse tunnel on [SSHHost](#sshhost-property-sshreversetunnel-component).

 **Service** *string (read-only)*
Default: ""

This field holds the channel type that was requested when opening the channel. For instance "session" or "forwarded-tcpip".

# Config Settings ([SSHReverseTunnel](#sshreversetunnel-component) Component)

 The component 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 component, access to these *internal properties* is provided through the [Config](#config-method-sshreversetunnel-component) method.

### SSHReverseTunnel Config Settings

**AutoReconnect**: Whether to automatically reconnect.This configuration setting controls automatic recovery of the Secure Shell (SSH) connection. If logon is disrupted or the channel is closed, the component can be configured to attempt reconnection automatically. Possible values follow:

| Value | Description |
| --- | --- |
| 0 (None) | Do not automatically reconnect. |
| 1 (Default) | Reconnect if an existing connection is broken. |
| 2 (Always) | Retry the initial logon as well as recover an existing connection. |

See [MaxRetryCount](#MaxRetryCount) and [RetryInterval](#RetryInterval) for additional related settings.

**DefaultChannelIdleTimeout**: The inactivity timeout for channels.This configuration setting specifies the idle timeout in seconds for each connected channel. If there is no activity on the channel for the specified timeout the channel is closed and the client is disconnected.

The default value is *0*, which is treated as an infinite timeout (the channel is never closed because of inactivity).

**ForwardedPort**: The remote port which is forwarded.When calling [RequestForwarding](#requestforwarding-method-sshreversetunnel-component) with a value of 0 for the port parameter, the server will assign the port automatically. This configuration setting may be queried to determine the port that was assigned by the server.

**ForwardingLocalHost**: The interface on which to bind when forwarding data.When the component is configured to automatically forward data to a destination, this configuration setting may be used to specify the interface to which the component binds when establishing the connection to the forwarding host.

This may be set to an IP address in the form *aaa.bbb.ccc.ddd*. By default this is unspecified and the system will automatically select the interface.

**MaxChannelCount**: Maximum number of open channels.This configuration setting specifies the maximum number of open channels that are allowed. If opening a channel would exceed this value the channel will not be opened and the [Error](#error-event-sshreversetunnel-component) event will be fired. The client will then be disconnected. The default value is *1024*.

**MaxChannelTransferRate[ChannelId]**: The transfer rate limit for a channel in bytes per second.This configuration setting can be used to throttle outbound Transmission Control Protocol (TCP) traffic on a specific channel. Set this to the number of bytes to be sent per second. By default, this is not set and there is no limit.

**MaxRetryCount**: The maximum number of retries when reconnecting.This configuration setting defines the maximum number of connection attempts performed when reestablishing a broken connection. This configuration setting applies only when [AutoReconnect](#AutoReconnect) is enabled. By default, the component will reconnect forever.

**RetryInterval**: The interval in seconds between reconnect attempts.This configuration setting specifies the number of seconds between reconnection attempts. This setting applies only when [AutoReconnect](#AutoReconnect) is enabled. The default value is *5*.

### SSHClient Config Settings

**ChannelDataEOL[ChannelId]**: Used to break the incoming data stream into chunks.By *default* [MaxChannelDataLength](#MaxChannelDataLength) is *0* and [ChannelDataEOL](#ChannelDataEOL) is an empty string. [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) fires whenever an SSH_MSG_CHANNEL_DATA packet is received.

If [MaxChannelDataLength](#MaxChannelDataLength) is greater than *0* and [ChannelDataEOL](#ChannelDataEOL) is a nonempty string, the component will internally buffer data waiting to fire [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) until either [MaxChannelDataLength](#MaxChannelDataLength) is reached or [ChannelDataEOL](#ChannelDataEOL) is found, whichever comes first. Query [ChannelDataEOLFound](#ChannelDataEOLFound) to know which condition was met. The buffer is reset any time [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) fires.

[ChannelDataEOL](#ChannelDataEOL) and [MaxChannelDataLength](#MaxChannelDataLength) *must* be set together or unexpected behavior could occur.

**ChannelDataEOLFound[ChannelId]**: Determines if ChannelDataEOL was found.If *true*,then [ChannelDataEOL](#ChannelDataEOL) was found. If *false*, then [MaxChannelDataLength](#MaxChannelDataLength) was reached.

This configuration setting is valid only when queried inside [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component), [MaxChannelDataLength](#MaxChannelDataLength) > 0, and [ChannelDataEOL](#ChannelDataEOL) is nonempty.

**ClientSSHVersionString**: The SSH version string used by the component.This configuration setting specifies the Secure Shell (SSH) version string used by the component. The default value is "SSH-2.0-IPWorks SSH Client 2024".

Most SSH servers expect the SSH version string to have the expected format "SSH-protocol version-software version". See above for an example.

**ConnectAndLogin**: Whether the component performs a full SSH login.The default value is *true*. When enabled, calling the Connect method establishes the TCP connection and performs a full SSH login.

When set to *false*, calling Connect will only establish the underlying TCP connection; the SSH login will not be performed. This may be useful in cases in which it is desirable to separate the connection and logon operations; for instance, confirming a host is available before authenticating with it.

When [ConnectAndLogin](#ConnectAndLogin) is *false*, call [SSHLogon](#sshlogon-method-sshreversetunnel-component) with the same [SSHHost](#sshhost-property-sshreversetunnel-component) and [SSHPort](#sshport-property-sshreversetunnel-component) used to connect in order to complete the SSH login over the existing connection. Note that [SSHLogon](#sshlogon-method-sshreversetunnel-component) always performs a full SSH login regardless of the value of this configuration setting.

**DoNotRepeatAuthMethods**: Whether the component will repeat authentication methods during multifactor authentication.The default value is *true*. When set to *false*, the component will repeat authentication methods that have already been completed during multifactor authentication.

**EnablePageantAuth**: Whether to use a key stored in Pageant to perform client authentication.This configuration setting controls whether Pageant authentication is disabled, enabled, or required. When enabled or required, the component attempts to communicate with PuTTY's ssh-agent, called "Pageant", over shared memory to perform public key authentication. Possible values and the corresponding behavior is described as follows:

| Value | Description |
| --- | --- |
| 0 (Disabled - default) | No communication with Pageant is attempted. |
| 1 (Enabled) | Pageant authentication is used if available. If Pageant is not running, or does not contain the expected key, no error is thrown. |
| 2 (Required) | Only Pageant authentication is used. If Pageant is not running, or does not contain the expected key, an error is thrown. |

**Example 1. Enabling Pageant:**

```text
component.Config("EnablePageantAuth=1");
component.SSHUser = "sshuser";
component.SSHLogon("localhost", 22);
```

NOTE: This functionality is available only on Windows.

**KerberosDelegation**: If true, asks for credentials with delegation enabled during authentication.The default value is "True". If set to "False", the client will not ask for credentials delegation support during authentication.

NOTE: Even if the client asks for delegation, the server/KDC might not grant it, and authentication will still succeed.

**KerberosRealm**: The fully qualified domain name of the Kerberos Realm to use for GSSAPI authentication.This property may be set to the fully qualified (DNS) name of the kerberos realm (or Windows Active Directory domain name) to use during GSSAPI authentication. This can be used to force authentication with a given realm if the client and server machines are not part of the same domain.

**KerberosSPN**: The Kerberos Service Principal Name of the SSH host.This property can be set to specify the Service Principal Name (SPN) associated with the SSH service on the remote host. This will usually be in the form "host/fqdn.of.sshhost[@REALM]". If not specified, the component will assume the SPN is based on the value of the [SSHHost](#sshhost-property-sshreversetunnel-component) property and the kerberos realm used for authentication.

**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-sshreversetunnel-component) 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. |

**MaxChannelDataLength[ChannelId]**: The maximum amount of data to accumulate when no ChannelDataEOL is found.By *default* [MaxChannelDataLength](#MaxChannelDataLength) is *0* and [ChannelDataEOL](#ChannelDataEOL) is an empty string. [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) fires whenever an SSH_MSG_CHANNEL_DATA packet is received.

If [MaxChannelDataLength](#MaxChannelDataLength) is greater than *0* and [ChannelDataEOL](#ChannelDataEOL) is a nonempty string, the component will internally buffer data waiting to fire [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) until either [MaxChannelDataLength](#MaxChannelDataLength) is reached or [ChannelDataEOL](#ChannelDataEOL) is found, whichever comes first. Query [ChannelDataEOLFound](#ChannelDataEOLFound) to know which condition was met. The buffer is reset any time [SSHChannelData](#sshchanneldata-event-sshreversetunnel-component) fires.

[ChannelDataEOL](#ChannelDataEOL) and [MaxChannelDataLength](#MaxChannelDataLength) *must* be set together or unexpected behavior could occur.

**MaxPacketSize**: The maximum packet size of the channel, in bytes.This configuration setting specifies the maximum size of an individual data packet, in bytes, that can be sent to the sender.

**MaxWindowSize**: The maximum window size allowed for the channel, in bytes.This configuration setting specifies how many bytes of channel data can be sent to the sender of this message without adjusting the window.

NOTE: This value may be changed during the connection, but the window size can only be increased, not decreased.

**NegotiatedStrictKex**: Returns whether strict key exchange was negotiated to be used.This configuration setting specifies whether strict key exchange (strict kex) was negotiated during the SSH handshake. 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")
```

**PasswordPrompt**: The text of the password prompt used in keyboard-interactive authentication.This configuration setting optionally specifies a pattern to be matched to the prompt received from the server during keyboard-interactive authentication. If a matching prompt is detected the component automatically responds to the prompt with the password specified by [SSHPassword](#sshpassword-property-sshreversetunnel-component).

This provides an easy way to automatically reply to prompts with the password if one is presented by the server. The password will be autofilled in the *Response* parameter of the [SSHKeyboardInteractive](#sshkeyboardinteractive-event-sshreversetunnel-component) event in the case of a match.

The following special characters are supported for pattern matching:

|  |  |
| --- | --- |
| ? | Any single character. |
| * | Any characters or no characters (e.g., C*t matches Cat, Cot, Coast, Ct). |
| [,-] | A range of characters (e.g., [a-z], [a], [0-9], [0-9,a-d,f,r-z]). |
| \ | The slash is ignored and exact matching is performed on the next character. |

If these characters need to be used as a literal in a pattern, then they must be escaped by surrounding them with brackets []. NOTE: "]" and "-" do not need to be escaped. See below for the escape sequences:

| Character | Escape Sequence |
| --- | --- |
| ? | [?] |
| * | [*] |
| [ | [[] |
| \ | [\] |

For example, to match the value [Something].txt, specify the pattern [[]Something].txt.

**PreferredDHGroupBits**: The size (in bits) of the preferred modulus (p) to request from the server.This configuration setting may be when using the diffie-hellman-group-exchange-sha1 or diffie-hellman-group-exchange-sha256 key exchange algorithms to control the preferred size, in bits, of the modulus (p) prime number to request from the server. Acceptable values are between 1024 and 8192.

**RecordLength**: The length of received data records.If set to a positive value, this configuration setting defines the length of data records to be received. The component will accumulate data until RecordLength is reached and only then will it fire the DataIn event with data of length RecordLength. This allows data to be received as records of known length. This value can be changed at any time, including within the DataIn event.

The default value is 0, meaning this setting is not used.

**ServerSSHVersionString**: The remote host's SSH version string.This configuration setting will return the remote host's SSH version string, which can help when identifying problematic servers. This configuration setting is read-only.

**SignedSSHCert**: The CA signed client public key used when authenticating.When authenticating via public key authentication, this setting may be set to the certificate authority (CA) signed client's public key. This is useful when the server has been configured to trust client keys signed by a particular CA. For instance:

```text
component.Config("SignedSSHCert=ssh-rsa-cert-v01@openssh.com AAAAB3NzaC1yc2EAAAADAQABAAAB...");
```

 The algorithm such as *ssh-rsa-cert-v01@openssh.com* in the previous string is used as part of the authentication process. To use a different algorithm, simply change this value. For instance, all of the following are acceptable with the same signed public key:

- *ssh-rsa-cert-v01@openssh.com AAAAB3NzaC1yc2EAAAADAQABAAAB...*
- *rsa-sha2-256-cert-v01@openssh.com AAAAB3NzaC1yc2EAAAADAQABAAAB...*
- *rsa-sha2-512-cert-v01@openssh.com AAAAB3NzaC1yc2EAAAADAQABAAAB...*

**SSHAcceptAnyServerHostKey**: If set the component will accept any key presented by the server.The default value is "False". Set this to "True" to accept any key presented by the server.

**SSHAcceptServerCAKey**: The CA public key that signed the server's host key.If the server's host key was signed by a CA, this configuration setting may be used to specify the CA's public key. If specified, the component will trust any server's host key that was signed by the CA. For instance:

```text
component.Config("SSHAcceptServerCAKey=ssh-rsa AAAAB3NzaC1yc2EAAAADAQAB...");
```

**SSHAcceptServerHostKeyFingerPrint**: The fingerprint(s) of the server host keys to accept.This configuration setting specifies one or more fingerprints that should be accepted as the servers host key. Each fingerprint should be represented using the hash algorithm and encoding format defined by the [SSHFingerprintHashAlgorithm](#SSHFingerprintHashAlgorithm) and [SSHFingerprintEncoding](#SSHFingerprintEncoding) configs, respectively.

By default, this config should be specified as the comma-separated list of hex-encoded SHA256 hashes of possible server host keys.

**Example:**

```text
// Assuming default values. Hex-encoded, SHA256 hash of the expected host key
SSHClient.Config("SSHAcceptServerHostKeyFingerPrint=61:2d:89:9c:55:67:5e:ca:22:86:fc:f6:07:59:67:e0:c7:77:08:1f:cc:d9:93:f3:f9:63:21:15:3e:0c:a2:1b");

// Base64-encoded, SHA256 hash of the expected host key
SSHClient.Config("SSHFingerprintEncoding=1");
SSHClient.Config("SSHAcceptServerHostKeyFingerPrint=n4bQgYhMfWWaL+qgxVrQFaO/TxsrC4Is0V1sFbDwCgg=");
```

 If the server's fingerprint matches one of the values supplied, the component will accept the host key.

**SSHFingerprintEncoding**: Specifies the encoding used when displaying the SSH host key fingerprint.This setting determines how the SSH host key fingerprint is displayed after it has been computed using the algorithm specified by [SSHFingerprintHashAlgorithm](#SSHFingerprintHashAlgorithm). Possible values are:

- *0* (Hex Encoded)
- *1* (Base64 Encoded - Default)

For example, when set to *0*, the Fingerprint parameter in [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) will be formatted like: *0a:1b:2c:3d*. When set to *1*, the Fingerprint parameter in [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) will be formatted like:

```plaintext
n4bQgYhMfWWaL+qgxVrQFaO/TxsrC4Is0V1sFbDwCgg=
```

.

Note that this config is also applicable when querying the [SSHFingerprintMD5](#SSHFingerprintMD5), [SSHFingerprintSHA1](#SSHFingerprintSHA1), or [SSHFingerprintSHA256](#SSHFingerprintSHA256) configuration settings.

Additionally, note that this config is also applicable if specifying the host key fingerprint via [SSHAcceptServerHostKeyFingerPrint](#SSHAcceptServerHostKeyFingerPrint). The value specified via [SSHAcceptServerHostKeyFingerPrint](#SSHAcceptServerHostKeyFingerPrint) should be specified according to the format or encoding specified by this configuration setting.

**SSHFingerprintHashAlgorithm**: The algorithm used to calculate the fingerprint.This configuration setting controls which hash algorithm is used to calculate the hostkey's fingerprint, displayed when [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) fires. Valid values are as follows:

- *MD5*
- *SHA1*
- *SHA256* (default)

**SSHFingerprintMD5**: The server hostkey's MD5 fingerprint.This configuration setting may be queried in [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) to get the server hostkey's MD5 fingerprint.

**SSHFingerprintSHA1**: The server hostkey's SHA1 fingerprint.This configuration setting may be queried in [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) to get the server hostkey's SHA-1 fingerprint.

**SSHFingerprintSHA256**: The server hostkey's SHA256 fingerprint.This configuration setting may be queried in [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) to get the server hostkey's SHA-256 fingerprint.

**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 component will continue to send keep-alive packets until [SSHKeepAliveCountMax](#SSHKeepAliveCountMax) is reached. If this is reached, the component 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 component 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](#sshreversetunnel-component) component 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*.

**SSHKeyRenegotiate**: Causes the component to renegotiate the SSH keys.Once this configuration setting is queried, the component will renegotiate the SSH keys with the remote host.

**Example 3. Renegotiating SSH Keys:**

```text
SSHClient.Config("SSHKeyRenegotiate")
```

**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 enabled signature algorithms that may be used when attempting public key authentication.This setting specifies a list of signature algorithms that may be used when authenticating to the server using public key authentication. This applies only when public key authentication is performed by the client.

The setting should be a comma-separated list of algorithms. At runtime, the component will evaluate the specified algorithms, and if the algorithm is applicable to the certificate specified in [SSHCert](#sshcert-property-sshreversetunnel-component), it will be used. If the algorithm is not applicable, the component will evaluate the next algorithm. Possible values are as 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,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519*.

**rsa-sha2-256 and rsa-sha2-512 notes**

The component will query the server for supported algorithms when connecting. If the server indicates support for *rsa-sha2-256* or *rsa-sha2-512* and the algorithm is present in the list defined by this setting (as in the default value), that algorithm will be used instead of *ssh-rsa* even when *ssh-rsa* appears first in the list.

For the *rsa-sha2-256* and *rsa-sha2-512* algorithms to be automatically preferred, the server must support the *ext-info-c* mechanism. In practice, older servers do not support this, and in that case, *ssh-rsa* will be used because it appears first in the list. Newer servers do support this mechanism, and in that case, *rsa-sha2-256* or *rsa-sha2-512* will be used even though it appears after *ssh-rsa*.

This behavior has been carefully designed to provide maximum compatibility while automatically using more secure algorithms when connecting to servers that support them.

**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-*
```

**TryAllAvailableAuthMethods**: If set to true, the component will try all available authentication methods.The default value is *false*. When set to *true*, the component will try to authenticate using all methods that it has credentials for and the server supports.

**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 component will indicate support for strict key exchange by automatically including the pseudo-algorithm *kex-strict-c-v00@openssh.com* for client components and *kex-strict-s-v00@openssh.com* for server components 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 component 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 component. |
| 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. |

**WaitForChannelClose**: Whether to wait for channels to be closed before disconnected.This configuration setting controls whether the component will wait for a server response to the SSH_MSG_CHANNEL_CLOSE when disconnecting. When the component disconnects, it will first attempt to close all open channels by sending a SSH_MSG_CHANNEL_CLOSE for each channel. This configuration setting controls whether the component will wait for a server response after sending the messages.

When *True* (default), the component will wait for a response to the channel close message until the responses have been received, the server closes the connection, or [Timeout](#timeout-property-sshreversetunnel-component) seconds is reached.

When *False*, the component will still send the channel close messages, but it will not wait for a response and will proceed to close the connection.

**WaitForServerDisconnect**: Whether to wait for the server to close the connection.This configuration setting controls whether to wait for the server to close the connection when [SSHLogoff](#sshlogoff-method-sshreversetunnel-component) is called.

When set to *True*, the component will initiate the disconnection sequence by sending SSH_MSG_DISCONNECT, but it will not close the connection and instead will wait for the server to close the connection. Setting this to True may be beneficial in circumstances in which many connections are being established, to avoid port exhaustion when sockets are in a TIME_WAIT state. Allowing the server to close the connection avoids the TIME_WAIT state of socket on the client machine.

When set to *False* (default), the client will close the connection. It is recommended to use this value unless there is a specific need to change it.

### TCPClient Config Settings

**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.

**ConnectionTimeout**: Sets a separate timeout value for establishing a connection.When set, this configuration setting allows you to specify a different timeout value for establishing a connection. Otherwise, the component will use [Timeout](#timeout-property-sshreversetunnel-component) for establishing a connection and transmitting/receiving data.

**FirewallAutoDetect**: Tells the component whether or not to automatically detect and use firewall system settings, if available.This configuration setting is provided for use by components that do not directly expose Firewall properties.

**FirewallHost**: Name or IP address of firewall (optional).If a [FirewallHost](#FirewallHost) is given, requested connections will be authenticated through the specified firewall when connecting.

If the [FirewallHost](#FirewallHost) setting is set to a Domain Name, a DNS request is initiated. Upon successful termination of the request, the [FirewallHost](#FirewallHost) setting is set to the corresponding address. If the search is not successful, an error is returned.

NOTE: This setting is provided for use by components that do not directly expose Firewall properties.

**FirewallHTTPVersion**: The HTTP version to be used when connecting through a tunneling proxy.When [FirewallType](#FirewallType) is set to a tunneling proxy, this setting dictates which HTTP version is used when connecting.

**FirewallListener**: If true, the component binds to a SOCKS firewall as a server (TCPClient only).This entry is for TCPClient only and does not work for other components that descend from TCPClient.

If this entry is set, the component acts as a server. RemoteHost and RemotePort are used to tell the SOCKS firewall in which address and port to listen to. The firewall rules may ignore RemoteHost, and it is recommended that RemoteHost be set to empty string in this case.

RemotePort is the port in which the firewall will listen to. If set to 0, the firewall will select a random port. The binding (address and port) is provided through the [ConnectionStatus](#connectionstatus-event-sshreversetunnel-component) event.

The connection to the firewall is made by calling the Connect method.

**FirewallPassword**: Password to be used if authentication is to be used when connecting through the firewall.If [FirewallHost](#FirewallHost) is specified, the [FirewallUser](#FirewallUser) and [FirewallPassword](#FirewallPassword) settings are used to connect and authenticate to the given firewall. If the authentication fails, the component throws an exception.

NOTE: This setting is provided for use by components that do not directly expose Firewall properties.

**FirewallPort**: The TCP port for the FirewallHost;.The [FirewallPort](#FirewallPort) is set automatically when [FirewallType](#FirewallType) is set to a valid value.

NOTE: This configuration setting is provided for use by components that do not directly expose Firewall properties.

**FirewallType**: Determines the type of firewall to connect through.Possible values are as follows:

|  |  |
| --- | --- |
| 0 | No firewall (default setting). |
| 1 | Connect through a tunneling proxy. [FirewallPort](#FirewallPort) is set to 80. |
| 2 | Connect through a SOCKS4 Proxy. [FirewallPort](#FirewallPort) is set to 1080. |
| 3 | Connect through a SOCKS5 Proxy. [FirewallPort](#FirewallPort) is set to 1080. |
| 10 | Connect through a SOCKS4A Proxy. [FirewallPort](#FirewallPort) is set to 1080. |

NOTE: This setting is provided for use by components that do not directly expose Firewall properties.

**FirewallUser**: A user name if authentication is to be used connecting through a firewall.If the [FirewallHost](#FirewallHost) is specified, the [FirewallUser](#FirewallUser) and [FirewallPassword](#FirewallPassword) settings are used to connect and authenticate to the Firewall. If the authentication fails, the component throws an exception.

NOTE: This setting is provided for use by components that do not directly expose Firewall properties.

**KeepAliveInterval**: The retry interval, in milliseconds, to be used when a TCP keep-alive packet is sent and no response is received.When set, [TCPKeepAlive](#TCPKeepAlive) will automatically be set to True. 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 configuration setting specifies the interval at which the successive keep-alive packets are sent in milliseconds. This system default if this value is not specified here is 1 second.

NOTE: This value is not applicable in macOS.

**KeepAliveTime**: The inactivity time in milliseconds before a TCP keep-alive packet is sent.When set, [TCPKeepAlive](#TCPKeepAlive) will automatically be set to True. By default, the operating system will determine the time a connection is idle before a Transmission Control Protocol (TCP) keep-alive packet is sent. This system default if this value is not specified here is 2 hours. In many cases, a shorter interval is more useful. Set this value to the desired interval in milliseconds.

**Linger**: When set to True, connections are terminated gracefully.This property controls how a connection is closed. The default is True.

In the case that Linger is True (default), two scenarios determine how long the connection will linger. In the first, if [LingerTime](#LingerTime) is 0 (default), the system will attempt to send pending data for a connection until the default IP timeout expires.

In the second scenario, if [LingerTime](#LingerTime) is a positive value, the system will attempt to send pending data until the specified [LingerTime](#LingerTime) is reached. If this attempt fails, then the system will reset the connection.

The default behavior (which is also the default mode for stream sockets) might result in a long delay in closing the connection. Although the component returns control immediately, the system could hold system resources until all pending data are sent (even after your application closes).

Setting this property to False forces an immediate disconnection. If you know that the other side has received all the data you sent (e.g., by a client acknowledgment), setting this property to False might be the appropriate course of action.

**LingerTime**: Time in seconds to have the connection linger. LingerTime is the time, in seconds, the socket connection will linger. This value is 0 by default, which means it will use the default IP timeout.

**LocalHost**: The name of the local host through which connections are initiated or accepted. The [LocalHost](#localhost-property-sshreversetunnel-component) setting 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 value of an interface will make the component initiate connections (or accept in the case of server components) only through that interface.

If the component is connected, the [LocalHost](#localhost-property-sshreversetunnel-component) setting 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).

**LocalPort**: The port in the local host where the component binds. This configuration setting must be set before a connection is attempted. It instructs the component to bind to a specific port (or communication endpoint) in the local machine.

Setting this to 0 (default) enables the system to choose a port at random. The chosen port will be shown by [LocalPort](#localport-property-sshreversetunnel-component) after the connection is established.

[LocalPort](#localport-property-sshreversetunnel-component) cannot be changed once a connection is made. Any attempt to set this when a connection is active will generate an error.

This configuration setting is useful when trying to connect to services that require a trusted port on the client side. An example is the remote shell (rsh) service in UNIX systems.

**MaxLineLength**: The maximum amount of data to accumulate when no EOL is found.[MaxLineLength](#MaxLineLength) is the size of an internal buffer, which holds received data while waiting for an EOL string.

If an EOL string is found in the input stream before [MaxLineLength](#MaxLineLength) bytes are received, the DataIn event is fired with the *EOL* parameter set to True, and the buffer is reset.

If no EOL is found, and [MaxLineLength](#MaxLineLength) bytes are accumulated in the buffer, the DataIn event is fired with the *EOL* parameter set to False, and the buffer is reset.

The minimum value for [MaxLineLength](#MaxLineLength) is 256 bytes. The default value is 2048 bytes.

**MaxTransferRate**: The transfer rate limit in bytes per second.This configuration setting can be used to throttle outbound TCP traffic. Set this to the number of bytes to be sent per second. By default, this is not set and there is no limit.

**ProxyExceptionsList**: A semicolon separated list of hosts and IPs to bypass when using a proxy.This configuration setting optionally specifies a semicolon-separated list of hostnames or IP addresses to bypass when a proxy is in use. When requests are made to hosts specified in this property, the proxy will not be used. For instance:

*www.google.com;www.example.com*

**TCPKeepAlive**: Determines whether or not the keep alive socket option is enabled.If set to True, the socket's keep-alive option is enabled and keep-alive packets will be sent periodically to maintain the connection. Set [KeepAliveTime](#KeepAliveTime) and [KeepAliveInterval](#KeepAliveInterval) to configure the timing of the keep-alive packets.

NOTE: This value is not applicable in Java.

**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 component will use IPv4 exclusively. When set to *1*, the component will use IPv6 exclusively. To instruct the component to prefer IPv6 addresses, but use IPv4 if IPv6 is not supported on the system, this setting should be set to *2*. The default value is *0*. Possible values are as follows:

|  |  |
| --- | --- |
| 0 | IPv4 only |
| 1 | IPv6 only |
| 2 | IPv6 with IPv4 fallback |

**UseNTLMv2**: Whether to use NTLM V2.When authenticating with NTLM, this setting specifies whether NTLM V2 is used. By default this value is True and NTLM V2 will be used. Set this to False to use NTLM V1.

### Socket Config Settings

**AbsoluteTimeout**: Determines whether timeouts are inactivity timeouts or absolute timeouts.If [AbsoluteTimeout](#AbsoluteTimeout) is set to True, any method that does not complete within [Timeout](#timeout-property-sshreversetunnel-component) seconds will be aborted. By default, *AbsoluteTimeout* is False, and the timeout is an inactivity timeout.

NOTE: This option is not valid for User Datagram Protocol (UDP) ports.

**FirewallData**: Used to send extra data to the firewall.When the firewall is a tunneling proxy, use this property to send custom (additional) headers to the firewall (e.g., headers for custom authentication schemes).

**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. In some cases, increasing the value of the *InBufferSize* setting can provide significant improvements in performance.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the *InBufferSize* reverts to its defined size. The same happens if you attempt to make it too large or too small.

**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. In some cases, increasing the value of the *OutBufferSize* setting can provide significant improvements in performance.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the *OutBufferSize* reverts to its defined size. The same happens if you attempt to make it too large or too small.

### 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 component 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 component 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 component 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*.

**UseFIPSCompliantAPI**: Tells the component whether or not to use FIPS certified APIs.When set to *true*, the component 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.

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 components 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: This setting is applicable only on Windows.

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 component will use the system security libraries by default to perform cryptographic functions where applicable. In this case, calls to unmanaged code will be made. In certain environments, this is not desirable. To use a completely managed security implementation, set this setting to *true*.

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

 On Windows, this setting is set to *false* by default. On Linux/macOS, this setting is set to *true* by default.

NOTE: This setting is static. The value set is applicable to all components used in the application.

When this value is set, the product's system dynamic link library (DLL) is no longer required as a reference, as all unmanaged code is stored in that file.

# Trappable Errors ([SSHReverseTunnel](#sshreversetunnel-component) Component)

### SSHReverseTunnel Errors

|  |  |
| --- | --- |
| 10057 | Reconnection limit exceeded for Secure Shell (SSH) tunnel. |

### SSHClient Errors

|  |  |
| --- | --- |
| 1001 | Server has disconnected. |
| 1002 | Protocol version unsupported or other issue with version string. |
| 1003 | Cannot negotiate algorithms. |
| 1005 | Selected algorithm unsupported. |
| 1006 | Cannot set keys. |
| 1010 | Unexpected algorithm. |
| 1011 | Cannot create exchange hash. |
| 1012 | Cannot make key. |
| 1013 | Cannot sign data. |
| 1014 | Cannot encrypt packet. |
| 1015 | Cannot decrypt packet. |
| 1016 | Cannot decompress packet. |
| 1020 | Failure to open channel. |
| 1021 | Invalid channel Id. |
| 1022 | Invalid channel data. |
| 1023 | Invalid channel message. |
| 1024 | SSH message unimplemented. |
| 1027 | Server message unsupported. |
| 1030 | Server's host key was rejected. The host key may be accepted within the [SSHServerAuthentication](#sshserverauthentication-event-sshreversetunnel-component) event or using the [SSHAcceptServerHostKey](#sshacceptserverhostkey-property-sshreversetunnel-component) property. |
| 1031 | Cannot verify server's host key. |
| 1032 | Authentication failed. Check description for details. |
| 1033 | Channel request failed. |
| 1034 | Diffie-Hellman exchange failed. |
| 1036 | SSH connection failed. |
| 1037 | SSH reconnect limit reached. |
| 1038 | Elliptic curve Diffie-Hellman exchange failed. |
| 1039 | SSH keep-alive limit reached. |
| 1098 | Request failure. |
| 1130 | Would block error. |
| 1133 | Would block, reason: key reExchange. |

The component may also return one of the following error codes, which are inherited from other components.

### TCPClient Errors

|  |  |
| --- | --- |
| 100 | You cannot change the RemotePort at this time. A connection is in progress. |
| 101 | You cannot change the RemoteHost (Server) at this time. A connection is in progress. |
| 102 | The RemoteHost address is invalid (0.0.0.0). |
| 104 | Already connected. If you want to reconnect, close the current connection first. |
| 106 | You cannot change the [LocalPort](#localport-property-sshreversetunnel-component) at this time. A connection is in progress. |
| 107 | You cannot change the [LocalHost](#localhost-property-sshreversetunnel-component) at this time. A connection is in progress. |
| 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. |
| 117 | You cannot change the UseConnection option while the component is active. |
| 135 | Operation would block. |
| 201 | Timeout. |
| 211 | Action impossible in control's present state. |
| 212 | Action impossible while not connected. |
| 213 | Action impossible while listening. |
| 301 | Timeout. |
| 303 | Could not open file. |
| 434 | Unable to convert string to selected CodePage. |
| 1105 | Already connecting. If you want to reconnect, close the current connection first. |
| 1117 | You need to connect first. |
| 1119 | You cannot change the LocalHost at this time. A connection is in progress. |
| 1120 | Connection dropped by remote host. |

### 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). |