SSHServer Component

Properties   Methods   Events   Config Settings   Errors  

The SSHServer component is used to create Secure Shell (SSH) servers. The component handles multiple simultaneous connections on the same Transmission Control Protocol (TCP)/IP port (service port). It is designed to balance the load between connections for a fast, powerful server.

Syntax

nsoftware.IPWorksSSH.SSHServer

Remarks

The SSHServer component is the Secure Shell (SSH)-enabled equivalent of the IPWorks TCPServer component, extended by a set of new properties and events that deal with SSH security. The SSHCompressionAlgorithms and SSHEncryptionAlgorithms properties determine which protocols are enabled for the SSH handshake. The SSHCert property is used to select a certificate for the server (note that a valid certificate must be selected before the server can function). The SSHUserAuthRequest event will allow you to use authenticate clients using digital certificates or passwords. Finally, the SSHStatus event provides information about the SSH handshake and underlying protocol notifications.

By default, each instance of SSHServer can handle up to 1000 simultaneous incoming connections (this number may be increased up to 100,000, or decreased to a lower value by using the MaxConnections configuration setting).

SSH connections are identified by a ConnectionId. Events relating to these connections as a whole will use the ConnectionId to identify the specific connection. Connections may also contain one or more multiplexed channels, which are identified by a ChannelId. Channel-level events will specify the ChannelId to which they relate.

SSHServer can start to listen on a port by setting the Listening property to True. When a remote host asks for a connection, the ConnectionRequest event is fired. At that point, the connection can either be accepted or rejected. If the connection is accepted, a ConnectionId is assigned, and communication can start. From this point on, the operation is similar to SSHClient. Data can be sent to an individual SSHChannel using SendChannelData. The address and port of the incoming connection can be found by querying the RemoteHost and RemotePort properties.

Threading in Server Applications

In .NET, all socket-based components perform all Socket.IO through asynchronous methods. Each call consumes a thread from the system's thread pool, and thus the number of concurrent calls is limited to the number of worker threads returned by System.Threading.ThreadPool.GetMaxThreads. When using several components that can each create a socket connection or a single component that can create multiple socket connections, the application may enter a state in which all of the pool threads are in use for receiving. In a scenario such as this, the remote hosts may be waiting for data from the application before sending, but the application cannot send that data because all the threads are tied up waiting for inbound data. This is particularly important for server applications that use a daemon component.

For example, say a server application 'S' has a max thread pool size of three, and clients 'A' and 'B' connect to it and each client uploads a large file. After all uploads are complete, 'S' enqueues an asynchronous read request in the thread pool for each client. Because no work is being done, the thread pool immediately consumes two threads that wait for any further data from 'A' and 'B'. While 'S' is still processing the first two files it has received, client 'C' connects and uploads a relatively small file. Similarly, once that upload has completed 'S' enqueues a third read request, and the thread pool immediately consumes the third and final thread to wait for further data from 'C'. Once 'S' completes processing any of the files, it will enqueue a send request. However, because all three threads are in use and waiting for data from the clients, the send operation cannot be completed. The entire system becomes deadlocked because each of the clients is waiting for data from the server, which cannot send that data because all of its pool threads are in turn waiting for data from the clients.

To avoid a deadlock situation such as this, it is necessary to ensure that the maximum number of socket connections an application can make is always at least one less than the number of available worker threads. One method to achieve this is to call System.Threading.ThreadPool.SetMaxThreads during the application's startup to set the maximum number of threads to a value high enough to support the application for the duration of its execution. Another option is to trap an event such as ConnectionRequest and Disconnected from each component instance with logic to manage the maximum thread pool size according to the application's current needs.

Note: Server components are designed to process events as they occur. To ensure that events are processed in a timely manner, DoEvents should be called in a loop after the server is started.

Property List

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

Method List

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

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.

Config Settings

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

Channels Property (SSHServer Component)

The collection of currently open channels.

Syntax

• C#
• VB.NET

public SSHChannelMap Channels { get; }

Public ReadOnly Property Channels As SSHChannelMap

Remarks

The Secure Shell (SSH) 2.0 specification allows for multiple channels to be opened over a single Transmission Control Protocol (TCP)/IP connection. The Channels property represents the channels that are currently open. A new SSHChannel can be opened with OpenChannel, and data can be sent over it with SendChannelData.

This collection is a hashtable where the channel's Id string is used as the key to the desired Secure Shell (SSH) channel object.

This property is read-only.

ConnectionBacklog Property (SSHServer Component)

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

Syntax

• C#
• VB.NET

public int ConnectionBacklog { get; set; }

Public Property ConnectionBacklog As Integer

Default Value

5

Remarks

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

This property is not available at design time.

Connections Property (SSHServer Component)

A collection of currently connected Secure Shell (SSH) clients.

Syntax

• C#
• VB.NET

public SSHConnectionMap Connections { get; }

Public ReadOnly Property Connections As SSHConnectionMap

Remarks

This property is a collection of currently connected clients. All of the connections may be managed using this property. Each connection is described by the different fields of the SSHConnection type.

This collection is a hashtable type of collection, in which the connection Id string is used as the key to the desired connection. You may acquire the key for a given connection through the Connected event.

This property is read-only.

DefaultAuthMethods Property (SSHServer Component)

The supported authentication methods.

Syntax

• C#
• VB.NET

public string DefaultAuthMethods { get; set; }

Public Property DefaultAuthMethods As String

Default Value

"password,publickey"

Remarks

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

This must be a comma-separated list of values. For more information on authenticating clients, see the SSHUserAuthRequest event.

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

DefaultIdleTimeout Property (SSHServer Component)

This property includes the default idle timeout for inactive clients.

Syntax

• C#
• VB.NET

public int DefaultIdleTimeout { get; set; }

Public Property DefaultIdleTimeout As Integer

Default Value

0

Remarks

This property specifies the idle timeout (in seconds) for clients. When set to a positive value, the component will disconnect idle clients after the specified timeout.

This applies only to clients that have not sent or received data within DefaultIdleTimeout seconds.

If set to 0 (default), no idle timeout is applied.

Note: DoEvents must be called for the component to check existing connections.

DefaultTimeout Property (SSHServer Component)

An initial timeout value to be used by incoming connections.

Syntax

• C#
• VB.NET

public int DefaultTimeout { get; set; }

Public Property DefaultTimeout As Integer

Default Value

60

Remarks

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

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

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

If Timeout expires, and the operation is not yet complete, the 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 DefaultTimeout property is 60 (seconds).

KeyboardInteractiveMessage Property (SSHServer Component)

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

Syntax

• C#
• VB.NET

public string KeyboardInteractiveMessage { get; set; }

Public Property KeyboardInteractiveMessage As String

Default Value

""

Remarks

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

KeyboardInteractivePrompts Property (SSHServer Component)

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

Syntax

• C#
• VB.NET

public SSHPromptList KeyboardInteractivePrompts { get; }

Public Property KeyboardInteractivePrompts As SSHPromptList

Remarks

This property is a collection of prompts to present to the user during keyboard-authentication. It is used together with the KeyboardInteractiveMessage property.

Listening Property (SSHServer Component)

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

Syntax

• C#
• VB.NET

public bool Listening { get; }

Public ReadOnly Property Listening As Boolean

Default Value

False

Remarks

This property indicates whether the component is listening for connections on the port specified by the LocalPort property. Use the StartListening and StopListening methods to control whether the component is listening.

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

LocalHost Property (SSHServer Component)

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

Syntax

• C#
• VB.NET

public string LocalHost { get; set; }

Public Property LocalHost As String

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 (SSHServer Component)

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

Syntax

• C#
• VB.NET

public int LocalPort { get; set; }

Public Property LocalPort As Integer

Default Value

22

Remarks

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

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

SSHCert Property (SSHServer Component)

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

Syntax

• C#
• VB.NET

public Certificate SSHCert { get; set; }

Public Property SSHCert As Certificate

Remarks

The digital certificate that the server will use during SSH negotiation. A certificate with a private key is required for session authentication and encryption.

This is the server's certificate, and must be set before setting Listening to True.

SSHCompressionAlgorithms Property (SSHServer Component)

The comma-separated list containing all allowable compression algorithms.

Syntax

• C#
• VB.NET

public string SSHCompressionAlgorithms { get; set; }

Public Property SSHCompressionAlgorithms As String

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 (SSHServer Component)

The comma-separated list containing all allowable encryption algorithms.

Syntax

• C#
• VB.NET

public string SSHEncryptionAlgorithms { get; set; }

Public Property SSHEncryptionAlgorithms As String

Default Value

"aes256-ctr,aes192-ctr,aes128-ctr,3des-ctr,arcfour256,arcfour128,arcfour,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:

ChangeRecordLength Method (SSHServer Component)

Changes the length of received data records.

Syntax

• C#
• VB.NET

public void ChangeRecordLength(string channelId, int recordLength);

Async Version
public async Task ChangeRecordLength(string channelId, int recordLength);
public async Task ChangeRecordLength(string channelId, int recordLength, CancellationToken cancellationToken);

Public Sub ChangeRecordLength(ByVal ChannelId As String, ByVal RecordLength As Integer)

Async Version
Public Sub ChangeRecordLength(ByVal ChannelId As String, ByVal RecordLength As Integer) As Task
Public Sub ChangeRecordLength(ByVal ChannelId As String, ByVal RecordLength As Integer, cancellationToken As CancellationToken) As Task

Remarks

This method defines the length of data records to be received (in bytes) for the specified ChannelId.

If RecordLength is set to a positive value, the component will accumulate data until RecordLength bytes of data is received and only then will it fire the SSHChannelDataIn event with data of length RecordLength. This allows data to be received as records of known length. This method can be called at any time to change the record length, including within the DataIn event.

A value of 0 (default) means this functionality is not used.

CloseChannel Method (SSHServer Component)

Closes an existing SSHChannel .

Syntax

• C#
• VB.NET

public void CloseChannel(string channelId);

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

Public Sub CloseChannel(ByVal ChannelId As String)

Async Version
Public Sub CloseChannel(ByVal ChannelId As String) As Task
Public Sub CloseChannel(ByVal ChannelId As String, cancellationToken As CancellationToken) As Task

Remarks

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

Config Method (SSHServer Component)

Sets or retrieves a configuration setting.

Syntax

• C#
• VB.NET

public string Config(string configurationString);

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

Public Function Config(ByVal ConfigurationString As String) As String

Async Version
Public Function Config(ByVal ConfigurationString As String) As Task(Of String)
Public Function Config(ByVal ConfigurationString As String, cancellationToken As CancellationToken) As Task(Of String)

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings 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, you must call Config("PROPERTY"). The value will be returned as a string.

Disconnect Method (SSHServer Component)

This method disconnects the specified client.

Syntax

• C#
• VB.NET

public void Disconnect(string connectionId);

Async Version
public async Task Disconnect(string connectionId);
public async Task Disconnect(string connectionId, CancellationToken cancellationToken);

Public Sub Disconnect(ByVal ConnectionId As String)

Async Version
Public Sub Disconnect(ByVal ConnectionId As String) As Task
Public Sub Disconnect(ByVal ConnectionId As String, cancellationToken As CancellationToken) As Task

Remarks

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

DoEvents Method (SSHServer Component)

This method processes events from the internal message queue.

Syntax

• C#
• VB.NET

public void DoEvents();

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

Public Sub DoEvents()

Async Version
Public Sub DoEvents() As Task
Public Sub DoEvents(cancellationToken As CancellationToken) As Task

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.

ExchangeKeys Method (SSHServer Component)

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

Syntax

• C#
• VB.NET

public void ExchangeKeys(string connectionId);

Async Version
public async Task ExchangeKeys(string connectionId);
public async Task ExchangeKeys(string connectionId, CancellationToken cancellationToken);

Public Sub ExchangeKeys(ByVal ConnectionId As String)

Async Version
Public Sub ExchangeKeys(ByVal ConnectionId As String) As Task
Public Sub ExchangeKeys(ByVal ConnectionId As String, cancellationToken As CancellationToken) As Task

Remarks

Secure Shell (SSH) key renegotiation can be initiated by either end of an established SSH connection. ExchangeKeys allows the server to start such a renegotiation with the client. During this process, SSHStatus 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. This makes it more difficult to break the security of data-intensive or long-lived connections.

GetSSHParam Method (SSHServer Component)

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

Syntax

• C#
• VB.NET

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);

Public Function GetSSHParam(ByVal Payload As String, ByVal Field As String) As String

Async Version
Public Function GetSSHParam(ByVal Payload As String, ByVal Field As String) As Task(Of String)
Public Function GetSSHParam(ByVal Payload As String, ByVal Field As String, cancellationToken As CancellationToken) As Task(Of String)

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. 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:

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:

x11-req

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

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:

exec

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

subsystem

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

xon-xoff

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

signal

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

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. 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.

GetSSHParamBytes Method (SSHServer Component)

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

Syntax

• C#
• VB.NET

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);

Public Function GetSSHParamBytes(ByVal Payload As String, ByVal Field As String) As String

Async Version
Public Function GetSSHParamBytes(ByVal Payload As String, ByVal Field As String) As Task(Of String)
Public Function GetSSHParamBytes(ByVal Payload As String, ByVal Field As String, cancellationToken As CancellationToken) As Task(Of String)

Remarks

This method is the same as calling GetSSHParam, but it returns raw bytes instead of strings.

OpenChannel Method (SSHServer Component)

Opens a new SSHChannel .

Syntax

• C#
• VB.NET

public string OpenChannel(string connectionId, string channelType);

Async Version
public async Task<string> OpenChannel(string connectionId, string channelType);
public async Task<string> OpenChannel(string connectionId, string channelType, CancellationToken cancellationToken);

Public Function OpenChannel(ByVal ConnectionId As String, ByVal ChannelType As String) As String

Async Version
Public Function OpenChannel(ByVal ConnectionId As String, ByVal ChannelType As String) As Task(Of String)
Public Function OpenChannel(ByVal ConnectionId As String, ByVal ChannelType As String, cancellationToken As CancellationToken) As Task(Of String)

Remarks

The Secure Shell (SSH) 2.0 specification allows for multiple channels to be opened over a single Transmission Control Protocol (TCP)/IP connection. The Channels property represents the channels that are currently open. A new SSHChannel can be opened with OpenChannel, and data can be sent over it with SendChannelData.

ChannelType represents the type of Secure Shell (SSH) channel to be opened. The most common type of channel is "session".

If the call to OpenChannel succeeds, an SSHChannel will be created and added to the Channels collection.

Reset Method (SSHServer Component)

This method will reset the component.

Syntax

• C#
• VB.NET

public void Reset();

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

Public Sub Reset()

Async Version
Public Sub Reset() As Task
Public Sub Reset(cancellationToken As CancellationToken) As Task

Remarks

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

SendBytes Method (SSHServer Component)

Sends binary data to the specified channel.

Syntax

• C#
• VB.NET

public void SendBytes(string channelId, byte[] data);

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

Public Sub SendBytes(ByVal ChannelId As String, ByVal Data As String)

Async Version
Public Sub SendBytes(ByVal ChannelId As String, ByVal Data As String) As Task
Public Sub SendBytes(ByVal ChannelId As String, ByVal Data As String, cancellationToken As CancellationToken) As Task

Remarks

This method sends binary data to the channel identified by ChannelId. To send text, use the SendText method instead.

SendChannelData Method (SSHServer Component)

Sends data over a Secure Shell (SSH) channel.

Syntax

• C#
• VB.NET

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);

Public Sub SendChannelData(ByVal ChannelId As String, ByVal Data As String)

Async Version
Public Sub SendChannelData(ByVal ChannelId As String, ByVal Data As String) As Task
Public Sub SendChannelData(ByVal ChannelId As String, ByVal Data As String, cancellationToken As CancellationToken) As Task

Remarks

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

SendSSHPacket Method (SSHServer Component)

Sends an encoded Secure Shell (SSH) packet to the server.

Syntax

• C#
• VB.NET

public void SendSSHPacket(string channelId, int packetType, byte[] payload);

Async Version
public async Task SendSSHPacket(string channelId, int packetType, byte[] payload);
public async Task SendSSHPacket(string channelId, int packetType, byte[] payload, CancellationToken cancellationToken);

Public Sub SendSSHPacket(ByVal ChannelId As String, ByVal PacketType As Integer, ByVal Payload As String)

Async Version
Public Sub SendSSHPacket(ByVal ChannelId As String, ByVal PacketType As Integer, ByVal Payload As String) As Task
Public Sub SendSSHPacket(ByVal ChannelId As String, ByVal PacketType As Integer, ByVal Payload As String, cancellationToken As CancellationToken) As Task

Remarks

This method can be used to send a previously built SSH payload to the server. ChannelId identifies the channel that will receive the packet.

PacketType identifies what kind of packet is to be sent. Payload should contain the payload of the packet, which can be built by successive calls to SetSSHParam.

When SendSSHPacket is called, the component will finish building the packet, encrypt it for transport, and send it to the server.

SendText Method (SSHServer Component)

Sends text to the specified channel.

Syntax

• C#
• VB.NET

public void SendText(string channelId, string text);

Async Version
public async Task SendText(string channelId, string text);
public async Task SendText(string channelId, string text, CancellationToken cancellationToken);

Public Sub SendText(ByVal ChannelId As String, ByVal Text As String)

Async Version
Public Sub SendText(ByVal ChannelId As String, ByVal Text As String) As Task
Public Sub SendText(ByVal ChannelId As String, ByVal Text As String, cancellationToken As CancellationToken) As Task

Remarks

This method sends text to the client identified by ChannelId. To send binary data, use the SendBytes method instead.

SetSSHParam Method (SSHServer Component)

Writes a field to the end of a payload.

Syntax

• C#
• VB.NET

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);

Public Function SetSSHParam(ByVal Payload As String, ByVal FieldType As String, ByVal FieldValue As String) As String

Async Version
Public Function SetSSHParam(ByVal Payload As String, ByVal FieldType As String, ByVal FieldValue As String) As Task(Of String)
Public Function SetSSHParam(ByVal Payload As String, ByVal FieldType As String, ByVal FieldValue As String, cancellationToken As CancellationToken) As Task(Of String)

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:

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

Shutdown Method (SSHServer Component)

This method shuts down the server.

Syntax

• C#
• VB.NET

public void Shutdown();

Async Version
public async Task Shutdown();
public async Task Shutdown(CancellationToken cancellationToken);

Public Sub Shutdown()

Async Version
Public Sub Shutdown() As Task
Public Sub Shutdown(cancellationToken As CancellationToken) As Task

Remarks

This method shuts down the server. Calling this method is equivalent to calling StopListening and then breaking every client connection by calling Disconnect.

StartListening Method (SSHServer Component)

This method starts listening for incoming connections.

Syntax

• C#
• VB.NET

public void StartListening();

Async Version
public async Task StartListening();
public async Task StartListening(CancellationToken cancellationToken);

Public Sub StartListening()

Async Version
Public Sub StartListening() As Task
Public Sub StartListening(cancellationToken As CancellationToken) As Task

Remarks

This method begins listening for incoming connections on the port specified by LocalPort. Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call StopListening. To stop listening for new connections and to disconnect all existing clients, call Shutdown.

StopListening Method (SSHServer Component)

This method stops listening for new connections.

Syntax

• C#
• VB.NET

public void StopListening();

Async Version
public async Task StopListening();
public async Task StopListening(CancellationToken cancellationToken);

Public Sub StopListening()

Async Version
Public Sub StopListening() As Task
Public Sub StopListening(cancellationToken As CancellationToken) As Task

Remarks

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

To stop listening and to disconnect all existing clients, call Shutdown instead.

Connected Event (SSHServer Component)

Fired immediately after a connection completes (or fails).

Syntax

• C#
• VB.NET

public event OnConnectedHandler OnConnected;

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

public class SSHServerConnectedEventArgs : EventArgs {
  public string ConnectionId { get; }
  public int StatusCode { get; }
  public string Description { get; }
  public int CertStoreType { get; set; }
  public string CertStore { get; set; }
  public string CertPassword { get; set; }
  public string CertSubject { get; set; }
}

Public Event OnConnected As OnConnectedHandler

Public Delegate Sub OnConnectedHandler(sender As Object, e As SSHServerConnectedEventArgs)

Public Class SSHServerConnectedEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property StatusCode As Integer
  Public ReadOnly Property Description As String
  Public Property CertStoreType As Integer
  Public Property CertStore As String
  Public Property CertPassword As String
  Public Property CertSubject As String
End Class

Remarks

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

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

Please refer to the Error Codes section for more information.

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

CertStoreType is the store type of the alternate certificate to use for this connection. The 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:

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

Designations of certificate stores are platform dependent.

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

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

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

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

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

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

ConnectionRequest Event (SSHServer Component)

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

Syntax

• C#
• VB.NET

public event OnConnectionRequestHandler OnConnectionRequest;

public delegate void OnConnectionRequestHandler(object sender, SSHServerConnectionRequestEventArgs e);

public class SSHServerConnectionRequestEventArgs : EventArgs {
  public string Address { get; }
  public int Port { get; }
  public bool Accept { get; set; }
}

Public Event OnConnectionRequest As OnConnectionRequestHandler

Public Delegate Sub OnConnectionRequestHandler(sender As Object, e As SSHServerConnectionRequestEventArgs)

Public Class SSHServerConnectionRequestEventArgs Inherits EventArgs
  Public ReadOnly Property Address As String
  Public ReadOnly Property Port As Integer
  Public Property Accept As Boolean
End Class

Remarks

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

Disconnected Event (SSHServer Component)

This event is fired when a connection is closed.

Syntax

• C#
• VB.NET

public event OnDisconnectedHandler OnDisconnected;

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

public class SSHServerDisconnectedEventArgs : EventArgs {
  public string ConnectionId { get; }
  public int StatusCode { get; }
  public string Description { get; }
}

Public Event OnDisconnected As OnDisconnectedHandler

Public Delegate Sub OnDisconnectedHandler(sender As Object, e As SSHServerDisconnectedEventArgs)

Public Class SSHServerDisconnectedEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property StatusCode As Integer
  Public ReadOnly Property Description As String
End Class

Remarks

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

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

Please refer to the Error Codes section for more information.

Error Event (SSHServer Component)

Fired when errors occur during data delivery.

Syntax

• C#
• VB.NET

public event OnErrorHandler OnError;

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

public class SSHServerErrorEventArgs : EventArgs {
  public string ConnectionId { get; }
  public int ErrorCode { get; }
  public string Description { get; }
}

Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As SSHServerErrorEventArgs)

Public Class SSHServerErrorEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ErrorCode As Integer
  Public ReadOnly Property Description As String
End Class

Remarks

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

ConnectionId contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Log Event (SSHServer Component)

Fired once for each log message.

Syntax

• C#
• VB.NET

public event OnLogHandler OnLog;

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

public class SSHServerLogEventArgs : EventArgs {
  public string ConnectionId { get; }
  public int LogLevel { get; }
  public string Message { get; }
  public string LogType { get; }
}

Public Event OnLog As OnLogHandler

Public Delegate Sub OnLogHandler(sender As Object, e As SSHServerLogEventArgs)

Public Class SSHServerLogEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property LogLevel As Integer
  Public ReadOnly Property Message As String
  Public ReadOnly Property LogType As String
End Class

Remarks

Fired once for each log message generated by the component. The verbosity is controlled by the LogLevel setting.

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

Message is the log message.

LogType is reserved for future use.

ConnectionId specifies the connection to which the log message is applicable.

SSHChannelClosed Event (SSHServer Component)

Fired when a channel is closed.

Syntax

• C#
• VB.NET

public event OnSSHChannelClosedHandler OnSSHChannelClosed;

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

public class SSHServerSSHChannelClosedEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string ChannelId { get; }
}

Public Event OnSSHChannelClosed As OnSSHChannelClosedHandler

Public Delegate Sub OnSSHChannelClosedHandler(sender As Object, e As SSHServerSSHChannelClosedEventArgs)

Public Class SSHServerSSHChannelClosedEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
End Class

Remarks

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

ConnectionId identifies the connection. ChannelId identifies the channel.

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.

SSHChannelDataIn Event (SSHServer Component)

Fired when data are received on a Secure Shell (SSH) channel.

Syntax

• C#
• VB.NET

public event OnSSHChannelDataInHandler OnSSHChannelDataIn;

public delegate void OnSSHChannelDataInHandler(object sender, SSHServerSSHChannelDataInEventArgs e);

public class SSHServerSSHChannelDataInEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string ChannelId { get; }
  public string Data { get; }
  public byte[] DataB { get; }
}

Public Event OnSSHChannelDataIn As OnSSHChannelDataInHandler

Public Delegate Sub OnSSHChannelDataInHandler(sender As Object, e As SSHServerSSHChannelDataInEventArgs)

Public Class SSHServerSSHChannelDataInEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
  Public ReadOnly Property Data As String
  Public ReadOnly Property DataB As Byte()
End Class

Remarks

Whenever a client sends data to an SSH channel, the SSHChannelDataIn event will fire. ChannelId will identify the channel receiving data. Data will contain the raw data being received.

ConnectionId identifies the connection. ChannelId identifies the channel.

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.

SSHChannelEOF Event (SSHServer Component)

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

Syntax

• C#
• VB.NET

public event OnSSHChannelEOFHandler OnSSHChannelEOF;

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

public class SSHServerSSHChannelEOFEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string ChannelId { get; }
}

Public Event OnSSHChannelEOF As OnSSHChannelEOFHandler

Public Delegate Sub OnSSHChannelEOFHandler(sender As Object, e As SSHServerSSHChannelEOFEventArgs)

Public Class SSHServerSSHChannelEOFEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
End Class

Remarks

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

ConnectionId identifies the connection. ChannelId identifies the channel.

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 (SSHServer Component)

Fired when a channel is successfully opened.

Syntax

• C#
• VB.NET

public event OnSSHChannelOpenedHandler OnSSHChannelOpened;

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

public class SSHServerSSHChannelOpenedEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string ChannelId { get; }
}

Public Event OnSSHChannelOpened As OnSSHChannelOpenedHandler

Public Delegate Sub OnSSHChannelOpenedHandler(sender As Object, e As SSHServerSSHChannelOpenedEventArgs)

Public Class SSHServerSSHChannelOpenedEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
End Class

Remarks

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

ConnectionId identifies the connection. ChannelId identifies the channel.

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 (SSHServer Component)

Fired when a client attempts to open a new channel.

Syntax

• C#
• VB.NET

public event OnSSHChannelOpenRequestHandler OnSSHChannelOpenRequest;

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

public class SSHServerSSHChannelOpenRequestEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string ChannelId { get; }
  public string Service { get; }
  public string Parameters { get; }
  public byte[] ParametersB { get; }
  public bool Accept { get; set; }
}

Public Event OnSSHChannelOpenRequest As OnSSHChannelOpenRequestHandler

Public Delegate Sub OnSSHChannelOpenRequestHandler(sender As Object, e As SSHServerSSHChannelOpenRequestEventArgs)

Public Class SSHServerSSHChannelOpenRequestEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
  Public ReadOnly Property Service As String
  Public ReadOnly Property Parameters As String
  Public ReadOnly Property ParametersB As Byte()
  Public Property Accept As Boolean
End Class

Remarks

This event is fired whenever a client 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 (e.g., "session"). Set Accept to True to accept the channel open request.

ConnectionId identifies the connection. ChannelId identifies the channel.

If the channel open request contains extra information, it will be contained in Parameters; you can extract data from it using GetSSHParam and GetSSHParamBytes. The most common example of a request with parameters would be a request with Service set to "direct-tcpip" (for Secure Shell (SSH) tunneling); in that case Parameters will contain the host to connect (string), the port to connect (int), the originator IP address (string), and the originator Transmission Control Protocol (TCP) port (int).

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.

SSHChannelReadyToSend Event (SSHServer Component)

Fired when the component is ready to send data.

Syntax

• C#
• VB.NET

public event OnSSHChannelReadyToSendHandler OnSSHChannelReadyToSend;

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

public class SSHServerSSHChannelReadyToSendEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string ChannelId { get; }
}

Public Event OnSSHChannelReadyToSend As OnSSHChannelReadyToSendHandler

Public Delegate Sub OnSSHChannelReadyToSendHandler(sender As Object, e As SSHServerSSHChannelReadyToSendEventArgs)

Public Class SSHServerSSHChannelReadyToSendEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
End Class

Remarks

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

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

When Timeout 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 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 (SSHServer Component)

Fired when the SSHHost sends a channel request to the client.

Syntax

• C#
• VB.NET

public event OnSSHChannelRequestHandler OnSSHChannelRequest;

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

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

Public Event OnSSHChannelRequest As OnSSHChannelRequestHandler

Public Delegate Sub OnSSHChannelRequestHandler(sender As Object, e As SSHServerSSHChannelRequestEventArgs)

Public Class SSHServerSSHChannelRequestEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
  Public ReadOnly Property RequestType As String
  Public ReadOnly Property Packet As String
  Public ReadOnly Property PacketB As Byte()
  Public Property Success As Boolean
End Class

Remarks

The SSHHost may send requests that affect the status of a particular 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.

ConnectionId identifies the connection.

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 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 (SSHServer Component)

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

Syntax

• C#
• VB.NET

public event OnSSHChannelRequestedHandler OnSSHChannelRequested;

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

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

Public Event OnSSHChannelRequested As OnSSHChannelRequestedHandler

Public Delegate Sub OnSSHChannelRequestedHandler(sender As Object, e As SSHServerSSHChannelRequestedEventArgs)

Public Class SSHServerSSHChannelRequestedEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property ChannelId As String
  Public ReadOnly Property RequestType As String
  Public ReadOnly Property Packet As String
  Public ReadOnly Property PacketB As Byte()
End Class

Remarks

The SSHHost may send requests that affect the status of a particular 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.

ConnectionId identifies the connection.

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.

SSHServiceRequest Event (SSHServer Component)

Fired when a client requests a service to be started.

Syntax

• C#
• VB.NET

public event OnSSHServiceRequestHandler OnSSHServiceRequest;

public delegate void OnSSHServiceRequestHandler(object sender, SSHServerSSHServiceRequestEventArgs e);

public class SSHServerSSHServiceRequestEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string Service { get; }
  public bool Accept { get; set; }
}

Public Event OnSSHServiceRequest As OnSSHServiceRequestHandler

Public Delegate Sub OnSSHServiceRequestHandler(sender As Object, e As SSHServerSSHServiceRequestEventArgs)

Public Class SSHServerSSHServiceRequestEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property Service As String
  Public Property Accept As Boolean
End Class

Remarks

The SSHServiceRequest event is fired when a client requests that a service be started for a particular connection, identified by ConnectionId. Service will be the name of the service the client wishes to start. If the connection is authenticated and the user has access to the service, set Accept to True to allow the SSHServer to accept the request.

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.

SSHStatus Event (SSHServer Component)

Fired to show the progress of the secure connection.

Syntax

• C#
• VB.NET

public event OnSSHStatusHandler OnSSHStatus;

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

public class SSHServerSSHStatusEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string Message { get; }
}

Public Event OnSSHStatus As OnSSHStatusHandler

Public Delegate Sub OnSSHStatusHandler(sender As Object, e As SSHServerSSHStatusEventArgs)

Public Class SSHServerSSHStatusEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property Message As String
End Class

Remarks

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

SSHTunnelClosed Event (SSHServer Component)

Fired when a connected client attempts to close a tunnel.

Syntax

• C#
• VB.NET

public event OnSSHTunnelClosedHandler OnSSHTunnelClosed;

public delegate void OnSSHTunnelClosedHandler(object sender, SSHServerSSHTunnelClosedEventArgs e);

public class SSHServerSSHTunnelClosedEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string Address { get; }
  public int Port { get; }
}

Public Event OnSSHTunnelClosed As OnSSHTunnelClosedHandler

Public Delegate Sub OnSSHTunnelClosedHandler(sender As Object, e As SSHServerSSHTunnelClosedEventArgs)

Public Class SSHServerSSHTunnelClosedEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property Address As String
  Public ReadOnly Property Port As Integer
End Class

Remarks

SSHTunnelRequested Event (SSHServer Component)

Fired when a connected client attempts to establish a forward or reverse tunnel.

Syntax

• C#
• VB.NET

public event OnSSHTunnelRequestedHandler OnSSHTunnelRequested;

public delegate void OnSSHTunnelRequestedHandler(object sender, SSHServerSSHTunnelRequestedEventArgs e);

public class SSHServerSSHTunnelRequestedEventArgs : EventArgs {
  public string ConnectionId { get; }
  public int Direction { get; }
  public string Address { get; }
  public int Port { get; set; }
  public bool Accept { get; set; }
}

Public Event OnSSHTunnelRequested As OnSSHTunnelRequestedHandler

Public Delegate Sub OnSSHTunnelRequestedHandler(sender As Object, e As SSHServerSSHTunnelRequestedEventArgs)

Public Class SSHServerSSHTunnelRequestedEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property Direction As Integer
  Public ReadOnly Property Address As String
  Public Property Port As Integer
  Public Property Accept As Boolean
End Class

Remarks

SSHUserAuthRequest Event (SSHServer Component)

Fired when a client attempts to authenticate a connection.

Syntax

• C#
• VB.NET

public event OnSSHUserAuthRequestHandler OnSSHUserAuthRequest;

public delegate void OnSSHUserAuthRequestHandler(object sender, SSHServerSSHUserAuthRequestEventArgs e);

public class SSHServerSSHUserAuthRequestEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string User { get; }
  public string Service { get; }
  public string AuthMethod { get; }
  public string AuthParam { get; }
  public bool Accept { get; set; }
  public bool PartialSuccess { get; set; }
  public string AvailableMethods { get; set; }
  public string KeyAlgorithm { get; }
}

Public Event OnSSHUserAuthRequest As OnSSHUserAuthRequestHandler

Public Delegate Sub OnSSHUserAuthRequestHandler(sender As Object, e As SSHServerSSHUserAuthRequestEventArgs)

Public Class SSHServerSSHUserAuthRequestEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionId As String
  Public ReadOnly Property User As String
  Public ReadOnly Property Service As String
  Public ReadOnly Property AuthMethod As String
  Public ReadOnly Property AuthParam As String
  Public Property Accept As Boolean
  Public Property PartialSuccess As Boolean
  Public Property AvailableMethods As String
  Public ReadOnly Property KeyAlgorithm As String
End Class

Remarks

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

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

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

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

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

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

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

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

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

Certificate Type

This is the digital certificate being used.

Remarks

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

Fields

Constructors

• C#
• VB.NET

public Certificate();

Public Certificate()

• C#
• VB.NET

public Certificate(string certificateFile);

Public Certificate(ByVal CertificateFile As String)

• C#
• VB.NET

public Certificate(byte[] encoded);

Public Certificate(ByVal Encoded As Byte())

• C#
• VB.NET

public Certificate(CertStoreTypes storeType, string store, string storePassword, string subject);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As String, ByVal StorePassword As String, ByVal Subject As String)

• C#
• VB.NET

public Certificate(CertStoreTypes storeType, string store, string storePassword, string subject, string configurationString);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As String, ByVal StorePassword As String, ByVal Subject As String, ByVal ConfigurationString As String)

• C#
• VB.NET

public Certificate(CertStoreTypes storeType, string store, string storePassword, byte[] encoded);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As String, ByVal StorePassword As String, ByVal Encoded As Byte())

• C#
• VB.NET

public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, string subject);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As Byte(), ByVal StorePassword As String, ByVal Subject As String)

• C#
• VB.NET

public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, string subject, string configurationString);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As Byte(), ByVal StorePassword As String, ByVal Subject As String, ByVal ConfigurationString As String)

• C#
• VB.NET

public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, byte[] encoded);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As Byte(), ByVal StorePassword As String, ByVal Encoded As Byte())

SSHChannel Type

Describes a currently open Secure Shell (SSH) channel.

Remarks

This type describes the Secure Shell (SSH) client's currently open channels. You may use the different fields for this type to manage the channel.

Fields

SSHConnection Type

A currently connected client.

Remarks

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

Fields

Constructors

• C#
• VB.NET

public SSHConnection();

Public SSHConnection()

SSHPrompt Type

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

Remarks

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

Fields

Constructors

• C#
• VB.NET

public SSHPrompt();

Public SSHPrompt()

• C#
• VB.NET

public SSHPrompt(string prompt, bool echo);

Public SSHPrompt(ByVal Prompt As String, ByVal Echo As Boolean)

Config Settings (SSHServer Component)

SSHServer Config Settings

*SSH-1.99-*,*SSH-2.0-*,*SSH-2.99-*

TCPServer Config Settings

Base Config Settings

Trappable Errors (SSHServer Component)

SSHServer Errors

TCPServer Errors

TCP/IP Errors