DataFlex

SSH Tunnel Timeouts and IP Preference

Demonstrates the ConnectTimeoutMs, IdleTimeoutMs, and PreferIpv6 properties, which govern how long the tunnel waits to connect and to transfer data, and which IP version it prefers.

Background: ConnectTimeoutMs bounds how long a connection attempt blocks — important so an unreachable server fails promptly instead of hanging — while IdleTimeoutMs guards against a stalled transfer holding a connection open indefinitely. PreferIpv6 only matters when a hostname resolves to both address families, choosing which to try first; the default prefers IPv4.

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DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoTunnel
    Integer iSshPort
    String sPassword
    Integer iListenPort
    Boolean iWaitForThreadExit
    String sTemp1

    Move False To iSuccess

    //  Demonstrates the SshTunnel connection-behavior properties ConnectTimeoutMs, IdleTimeoutMs, and
    //  PreferIpv6.

    Get Create (RefClass(cComChilkatSshTunnel)) To hoTunnel
    If (Not(IsComObjectCreated(hoTunnel))) Begin
        Send CreateComObject of hoTunnel
    End

    //  Maximum time to establish the SSH connection (default 30000 ms).
    Set ComConnectTimeoutMs Of hoTunnel To 10000

    //  Stall timeout for tunnel data-transfer operations (default 30000 ms).
    Set ComIdleTimeoutMs Of hoTunnel To 15000

    //  When a hostname resolves to both IPv4 and IPv6, prefer IPv6.  The default (False) prefers IPv4.
    Set ComPreferIpv6 Of hoTunnel To True

    Set ComDestHostname Of hoTunnel To "db.internal.example.com"
    Set ComDestPort Of hoTunnel To 5432

    Move 22 To iSshPort
    Get ComConnect Of hoTunnel "ssh.example.com" iSshPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    Move "mySshPassword" To sPassword

    Get ComAuthenticatePw Of hoTunnel "mySshLogin" sPassword To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Move 1080 To iListenPort
    Get ComBeginAccepting Of hoTunnel iListenPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Tunnel established."

    Move True To iWaitForThreadExit
    Get ComCloseTunnel Of hoTunnel iWaitForThreadExit To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End



End_Procedure