SshTunnel DataFlex Reference Documentation

SshTunnel

Current Version: 9.5.0.73

The SSH tunnel class provides for the ability to run a self-contained SSH tunnel in a background thread. It can behave as a SOCKS proxy, accepting connections from SOCKS4 or SOCK5 proxy clients and fowarding connections through an SSH tunnel. This is the "dynamic port forwarding" mode of operation. It can also behave in a static port forwarding mode (where it accepts connections and forwards the connection to a pre-defined remote destination IP:port).

Object Creation

// (Dataflex programs use the 32-bit Chilkat ActiveX)
Handle hoSshTunnel
Get Create(RefClass(cComChilkatSshTunnel)) to hoSshTunnel

Properties

AbortCurrent
Function ComAbortCurrent Returns Boolean
Procedure Set ComAbortCurrent Boolean value
Introduced in version 9.5.0.58

When set to True, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to False when the next method is called. When the abort occurs, this property is reset to False. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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AcceptLog
Function ComAcceptLog Returns String
Procedure Set ComAcceptLog String value

Contains an in-memory log of the listen thread. This will only contain content if the KeepAcceptLog property is True.

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AcceptLogPath
Function ComAcceptLogPath Returns String
Procedure Set ComAcceptLogPath String value
Introduced in version 9.5.0.50

Specifies a log file to be kept for the activity in the listen thread.

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ConnectTimeoutMs
Function ComConnectTimeoutMs Returns Integer
Procedure Set ComConnectTimeoutMs Integer value

Maximum number of milliseconds to wait when connecting to an SSH server. The default value is 10000 (i.e. 10 seconds). A value of 0 indicates no timeout (wait forever).

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DebugLogFilePath
Function ComDebugLogFilePath Returns String
Procedure Set ComDebugLogFilePath String value

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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DestHostname
Function ComDestHostname Returns String
Procedure Set ComDestHostname String value

The destination hostname or IP address (in dotted decimal notation) of the service (such as a database server). Data sent through the SSH tunnel is forwarded by the SSH server to this destination. Data received from the destination (by the SSH server) is forwarded back to the client through the SSH tunnel.

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DestPort
Function ComDestPort Returns Integer
Procedure Set ComDestPort Integer value

The destination port of the service (such as a database server).

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DynamicPortForwarding
Function ComDynamicPortForwarding Returns Boolean
Procedure Set ComDynamicPortForwarding Boolean value
Introduced in version 9.5.0.50

If True, then this behaves as a SOCKS proxy server for inbound connections. When this property is True, the DestHostname and DestPort properties are unused because the destination IP:port is dynamically provided by the SOCKS client. The default value of this property is False.

When dynamic port forwarding is used, the InboundSocksVersion property must be set to 4 or 5. If inbound SOCKS5 is used, then the InboundSocksUsername and InboundSocksPassword may be set to the required login/password for a client to gain access.

More Information and Examples
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HostKeyFingerprint
Function ComHostKeyFingerprint Returns String
Introduced in version 9.5.0.56

Set after connecting to an SSH server. The format of the fingerprint looks like this: "ssh-rsa 1024 68:ff:d1:4e:6c:ff:d7:b0:d6:58:73:85:07:bc:2e:d5"

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HttpProxyAuthMethod
Function ComHttpProxyAuthMethod Returns String
Procedure Set ComHttpProxyAuthMethod String value

If an HTTP proxy requiring authentication is to be used, set this property to the HTTP proxy authentication method name. Valid choices are "Basic" or "NTLM".

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through an HTTP proxy.

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HttpProxyDomain
Function ComHttpProxyDomain Returns String
Procedure Set ComHttpProxyDomain String value

The NTLM authentication domain (optional) if NTLM authentication is used w/ the HTTP proxy.

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through an HTTP proxy.

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HttpProxyHostname
Function ComHttpProxyHostname Returns String
Procedure Set ComHttpProxyHostname String value

If an HTTP proxy is to be used, set this property to the HTTP proxy hostname or IPv4 address (in dotted decimal notation).

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through an HTTP proxy.

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HttpProxyPassword
Function ComHttpProxyPassword Returns String
Procedure Set ComHttpProxyPassword String value

If an HTTP proxy requiring authentication is to be used, set this property to the HTTP proxy password.

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through an HTTP proxy.

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HttpProxyPort
Function ComHttpProxyPort Returns Integer
Procedure Set ComHttpProxyPort Integer value

If an HTTP proxy is to be used, set this property to the HTTP proxy port number. (Two commonly used HTTP proxy ports are 8080 and 3128.)

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through an HTTP proxy.

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HttpProxyUsername
Function ComHttpProxyUsername Returns String
Procedure Set ComHttpProxyUsername String value

If an HTTP proxy requiring authentication is to be used, set this property to the HTTP proxy login name.

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through an HTTP proxy.

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IdleTimeoutMs
Function ComIdleTimeoutMs Returns Integer
Procedure Set ComIdleTimeoutMs Integer value

A tunnel will fail when progress for sending or receiving data halts for more than this number of milliseconds. The default value is 10,000 (which is 10 seconds). A timeout of 0 indicates an infinite wait time (i.e. no timeout).

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InboundSocksPassword
Function ComInboundSocksPassword Returns String
Procedure Set ComInboundSocksPassword String value
Introduced in version 9.5.0.50

If dynamic port forwarding is used, then this may be set to the password required for authenticating inbound connections.

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InboundSocksUsername
Function ComInboundSocksUsername Returns String
Procedure Set ComInboundSocksUsername String value
Introduced in version 9.5.0.50

If dynamic port forwarding is used, then this may be set to the username required for authenticating inbound connections. If no username is set, then the inbound connection needs no authentication.

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IsAccepting
Function ComIsAccepting Returns Boolean

True if a background thread is running and accepting connections.

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KeepAcceptLog
Function ComKeepAcceptLog Returns Boolean
Procedure Set ComKeepAcceptLog Boolean value

If True, then an in-memory log of the listen thread is kept. The default value is False.

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KeepTunnelLog
Function ComKeepTunnelLog Returns Boolean
Procedure Set ComKeepTunnelLog Boolean value
Introduced in version 9.5.0.50

If True, then a log of the SSH tunnel thread activity is kept in memory. The default value is False.

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LastBinaryResult
Function ComLastBinaryResult Returns Variant
Introduced in version 9.5.0.52

The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to True. This provides a means for obtaining large varbinary results in the SQL Server environment (where limitations exist in getting large amounts of data returned by method calls, but where temp tables can be used for binary properties).

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LastErrorHtml
Function ComLastErrorHtml Returns String

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
Function ComLastErrorText Returns String

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
Function ComLastErrorXml Returns String

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
Function ComLastMethodSuccess Returns Boolean
Procedure Set ComLastMethodSuccess Boolean value
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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LastStringResult
Function ComLastStringResult Returns String
Introduced in version 9.5.0.52

The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to True. This provides a means for obtaining large string results in the SQL Server environment (where limitations exist in getting long strings returned by method calls, but where temp tables can be used for string properties).

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LastStringResultLen
Function ComLastStringResultLen Returns Integer
Introduced in version 9.5.0.53

The length, in characters, of the string contained in the LastStringResult property.

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ListenBindIpAddress
Function ComListenBindIpAddress Returns String
Procedure Set ComListenBindIpAddress String value

In most cases, this property does not need to be set. It is provided for cases where it is required to bind the listen socket to a specific IP address (usually for computers with multiple network interfaces or IP addresses). For computers with a single network interface (i.e. most computers), this property should not be set. For multihoming computers, the default IP address is automatically used if this property is not set.

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ListenPort
Function ComListenPort Returns Integer

If a port number equal to 0 is passed to BeginAccepting, then this property will contain the actual allocated port number used. Otherwise it is equal to the port number passed to BeginAccepting, or 0 if BeginAccepting was never called.

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OutboundBindIpAddress
Function ComOutboundBindIpAddress Returns String
Procedure Set ComOutboundBindIpAddress String value

In most cases, this property does not need to be set. It is provided for cases where it is required to bind the socket that is to connect to the SSH server (in the background thread) to a specific IP address (usually for computers with multiple network interfaces or IP addresses). For computers with a single network interface (i.e. most computers), this property should not be set. For multihoming computers, the default IP address is automatically used if this property is not set.

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OutboundBindPort
Function ComOutboundBindPort Returns Integer
Procedure Set ComOutboundBindPort Integer value

Unless there is a specific requirement for binding to a specific port, leave this unset (at the default value of 0). (99.9% of all users should never need to set this property.)

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PreferIpv6
Function ComPreferIpv6 Returns Boolean
Procedure Set ComPreferIpv6 Boolean value
Introduced in version 9.5.0.70

If True, then use IPv6 over IPv4 when both are supported for a particular domain. The default value of this property is False, which will choose IPv4 over IPv6.

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SocksHostname
Function ComSocksHostname Returns String
Procedure Set ComSocksHostname String value

The SOCKS4/SOCKS5 hostname or IPv4 address (in dotted decimal notation). This property is only used if the SocksVersion property is set to 4 or 5).

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through a SOCKS4 or SOCKS5 proxy.

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SocksPassword
Function ComSocksPassword Returns String
Procedure Set ComSocksPassword String value

The SOCKS5 password (if required). The SOCKS4 protocol does not include the use of a password, so this does not apply to SOCKS4.

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through a SOCKS4 or SOCKS5 proxy.

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SocksPort
Function ComSocksPort Returns Integer
Procedure Set ComSocksPort Integer value

The SOCKS4/SOCKS5 proxy port. The default value is 1080. This property only applies if a SOCKS proxy is used (if the SocksVersion property is set to 4 or 5).

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through a SOCKS4 or SOCKS5 proxy.

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SocksUsername
Function ComSocksUsername Returns String
Procedure Set ComSocksUsername String value

The SOCKS4/SOCKS5 proxy username. This property is only used if the SocksVersion property is set to 4 or 5).

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through a SOCKS4 or SOCKS5 proxy.

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SocksVersion
Function ComSocksVersion Returns Integer
Procedure Set ComSocksVersion Integer value

SocksVersion May be set to one of the following integer values:

0 - No SOCKS proxy is used. This is the default.
4 - Connect via a SOCKS4 proxy.
5 - Connect via a SOCKS5 proxy.

Note: This is for the outbound connection to the SSH server. It is used when the outbound connection to the SSH server must go through a SOCKS4 or SOCKS5 proxy.

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SoRcvBuf
Function ComSoRcvBuf Returns Integer
Procedure Set ComSoRcvBuf Integer value

Sets the receive buffer size socket option. Normally, this property should be left unchanged. The default value is 4194304.

This property can be increased if download performance seems slow. It is recommended to be a multiple of 4096.

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SoSndBuf
Function ComSoSndBuf Returns Integer
Procedure Set ComSoSndBuf Integer value

Sets the send buffer size socket option. Normally, this property should be left unchanged. The default value is 262144.

This property can be increased if upload performance seems slow. It is recommended to be a multiple of 4096. Testing with sizes such as 512K and 1MB is reasonable.

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TcpNoDelay
Function ComTcpNoDelay Returns Boolean
Procedure Set ComTcpNoDelay Boolean value

Controls whether the TCP_NODELAY socket option is used for the underlying TCP/IP socket. The default value is False. Setting this property equal to True disables the Nagle algorithm and allows for better performance when small amounts of data are sent.

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TunnelLog
Function ComTunnelLog Returns String
Procedure Set ComTunnelLog String value
Introduced in version 9.5.0.50

Contains an in-memory log of the SSH tunnel thread. This will only contain content if the KeepTunnelLog property is True.

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TunnelLogPath
Function ComTunnelLogPath Returns String
Procedure Set ComTunnelLogPath String value
Introduced in version 9.5.0.50

Set to keep a log file of the SSH tunnel thread.

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UncommonOptions
Function ComUncommonOptions Returns String
Procedure Set ComUncommonOptions String value
Introduced in version 9.5.0.73

This is a catch-all property to be used for uncommon needs. This property defaults to the empty string, and should typically remain empty.

As of v9.5.0.73, the only possible value is:

  • "KEX_DH_GEX_REQUEST_OLD" - Force the old Group Exchange message to be used. This would be used for very old SSH server implementations that do not use the RFC standard for diffie-hellman-group-exchange.

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VerboseLogging
Function ComVerboseLogging Returns Boolean
Procedure Set ComVerboseLogging Boolean value

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
Function ComVersion Returns String

Version of the component/library, such as "9.5.0.63"

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Methods

AuthenticatePk
Function ComAuthenticatePk String username cComChilkatSshKey privateKey Returns Boolean
Introduced in version 9.5.0.50

Authenticates with the SSH server using public-key authentication. The corresponding public key must have been installed on the SSH server for the username. Authentication will succeed if the matching privateKey is provided.

Important: When reporting problems, please send the full contents of the LastErrorText property to support@chilkatsoft.com.

Returns True for success, False for failure.

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AuthenticatePkAsync (1)
Function ComAuthenticatePkAsync String username cComChilkatSshKey privateKey Returns cComChilkatTask
Introduced in version 9.5.0.50

Creates an asynchronous task to call the AuthenticatePk method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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AuthenticatePw
Function ComAuthenticatePw String login String password Returns Boolean
Introduced in version 9.5.0.50

Authenticates with the SSH server using a login and password.

An SSH session always begins by first calling Connect to connect to the SSH server, and then calling either AuthenticatePw or AuthenticatePk to login.

Important: When reporting problems, please send the full contents of the LastErrorText property to support@chilkatsoft.com.
Note: To learn about how to handle password change requests, see the PasswordChangeRequested property (above).

Returns True for success, False for failure.

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AuthenticatePwAsync (1)
Function ComAuthenticatePwAsync String login String password Returns cComChilkatTask
Introduced in version 9.5.0.50

Creates an asynchronous task to call the AuthenticatePw method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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AuthenticatePwPk
Function ComAuthenticatePwPk String username String password cComChilkatSshKey privateKey Returns Boolean
Introduced in version 9.5.0.50

Authentication for SSH servers that require both a password and private key. (Most SSH servers are configured to require one or the other, but not both.)

Important: When reporting problems, please send the full contents of the LastErrorText property to support@chilkatsoft.com.

Returns True for success, False for failure.

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AuthenticatePwPkAsync (1)
Function ComAuthenticatePwPkAsync String username String password cComChilkatSshKey privateKey Returns cComChilkatTask
Introduced in version 9.5.0.50

Creates an asynchronous task to call the AuthenticatePwPk method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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AuthenticateSecPw
Function ComAuthenticateSecPw cComChilkatSecureString login cComChilkatSecureString password Returns Boolean
Introduced in version 9.5.0.71

The same as AuthenticatePw, except the login and password strings are passed in secure string objects.

Returns True for success, False for failure.

More Information and Examples
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AuthenticateSecPwAsync (1)
Function ComAuthenticateSecPwAsync cComChilkatSecureString login cComChilkatSecureString password Returns cComChilkatTask
Introduced in version 9.5.0.71

Creates an asynchronous task to call the AuthenticateSecPw method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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AuthenticateSecPwPk
Function ComAuthenticateSecPwPk cComChilkatSecureString username cComChilkatSecureString password cComChilkatSshKey privateKey Returns Boolean
Introduced in version 9.5.0.71

The same as AuthenticatePwPk, except the login and password strings are passed in secure string objects.

Returns True for success, False for failure.

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AuthenticateSecPwPkAsync (1)
Function ComAuthenticateSecPwPkAsync cComChilkatSecureString username cComChilkatSecureString password cComChilkatSshKey privateKey Returns cComChilkatTask
Introduced in version 9.5.0.71

Creates an asynchronous task to call the AuthenticateSecPwPk method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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BeginAccepting
Function ComBeginAccepting Integer listenPort Returns Boolean

Starts a background thread for listening on listenPort. A new SSH tunnel is created and managed for each accepted connection. SSH tunnels are managed in a 2nd background thread: the SSH tunnel pool thread.

BeginAccepting starts a background thread that creates a socket, binds to the port, and begins listening. If the bind fails (meaning something else may have already bound to the same port), then the background thread exits. You may check to see if BeginAccepting succeeds by waiting a short time (perhaps 50 millisec) and then examine the IsAccepting property. If it is False, then BeginAccepting failed.

Returns True for success, False for failure.

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BeginAcceptingAsync (1)
Function ComBeginAcceptingAsync Integer listenPort Returns cComChilkatTask

Creates an asynchronous task to call the BeginAccepting method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CloseTunnel
Function ComCloseTunnel Boolean waitForThreads Returns Boolean
Introduced in version 9.5.0.50

Closes the SSH tunnel and disconnects all existing clients. If waitForThreads is True, the method will wait for the tunnel and client threads to exit before returning.

Returns True for success, False for failure.

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Connect
Function ComConnect String hostname Integer port Returns Boolean
Introduced in version 9.5.0.50

Connects to the SSH server to be used for SSH tunneling.

Returns True for success, False for failure.

More Information and Examples
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ConnectAsync (1)
Function ComConnectAsync String hostname Integer port Returns cComChilkatTask
Introduced in version 9.5.0.50

Creates an asynchronous task to call the Connect method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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ConnectThroughSsh
Function ComConnectThroughSsh cComChilkatSsh ssh String hostname Integer port Returns Boolean
Introduced in version 9.5.0.55

Connects to an SSH server through an existing SSH connection. The ssh is an existing connected and authenticated SSH object. The connection to hostname:port is made through the existing SSH connection via port-forwarding. If successful, the connection is as follows: application => ServerSSH1 => ServerSSH2. (where ServerSSH1 is the ssh and ServerSSH2 is the SSH server at hostname:port) Once connected in this way, all communications are routed through ServerSSH1 to ServerSSH2. This includes authentication -- which means the application must still call one of the Authenticate* methods to authenticate with ServerSSH2.

Returns True for success, False for failure.

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ConnectThroughSshAsync (1)
Function ComConnectThroughSshAsync cComChilkatSsh ssh String hostname Integer port Returns cComChilkatTask
Introduced in version 9.5.0.55

Creates an asynchronous task to call the ConnectThroughSsh method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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DisconnectAllClients
Function ComDisconnectAllClients Boolean waitForThreads Returns Boolean
Introduced in version 9.5.0.50

Disconnects all clients, keeping the SSH tunnel open. If waitForThreads is True, the method will wait for the client threads to exit before returning.

Returns True for success, False for failure.

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GetCurrentState
Function ComGetCurrentState Returns String
Introduced in version 9.5.0.65

Returns the current state of existing tunnels in an XML string.

Returns null on failure

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IsSshConnected
Function ComIsSshConnected Returns Boolean
Introduced in version 9.5.0.61

Returns True if connected to the SSH server. Returns False if the connection has been lost (or was never established).

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StopAccepting
Function ComStopAccepting Boolean waitForThread Returns Boolean

Stops the listen background thread. It is possible to continue accepting connections by re-calling BeginAccepting. If waitForThread is True, the method will wait for the listen thread to exit before returning.

Returns True for success, False for failure.

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UnlockComponent
Function ComUnlockComponent String unlockCode Returns Boolean

Unlocks the component. This must be called once prior to calling any other method. A fully-functional 30-day trial is automatically started when an arbitrary string is passed to this method. For example, passing "Hello", or "abc123" will unlock the component for the 1st thirty days after the initial install.

Returns True for success, False for failure.

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