DataFlex

Connect to an SSH Server Through Another (Jump Host)

Demonstrates the Chilkat Ssh.ConnectThroughSsh method, which connects to a second SSH server through an already connected and authenticated Ssh object. The first argument is the first (jump-host) Ssh object, and the second and third are the destination hostname and port.

Background: This is SSH chaining through a "jump host" (bastion): the application connects to a reachable gateway, then tunnels onward to a target that is only accessible from inside the network. Each hop is authenticated separately with its own credentials. The result is a normal Ssh object for the target that happens to be routed through the first connection.

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Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vSshJump
    Handle hoSshJump
    Integer iSshPort
    String sPassword
    Handle hoSshTarget
    String sTemp1

    Move False To iSuccess

    //  Demonstrates the Ssh.ConnectThroughSsh method, which connects to a second SSH server through
    //  an already connected and authenticated Ssh object (a jump host).  The 1st argument is the
    //  first Ssh object, and the 2nd and 3rd are the destination hostname and port.

    Get Create (RefClass(cComChilkatSsh)) To hoSshJump
    If (Not(IsComObjectCreated(hoSshJump))) Begin
        Send CreateComObject of hoSshJump
    End

    //  Connect and authenticate to the first SSH server (the jump host).
    Move 22 To iSshPort
    Get ComConnect Of hoSshJump "jump.example.com" iSshPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSshJump 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 hoSshJump "jumpUser" sPassword To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSshJump To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Connect to the target SSH server through the jump host.
    Get Create (RefClass(cComChilkatSsh)) To hoSshTarget
    If (Not(IsComObjectCreated(hoSshTarget))) Begin
        Send CreateComObject of hoSshTarget
    End
    Get pvComObject of hoSshJump to vSshJump
    Get ComConnectThroughSsh Of hoSshTarget vSshJump "target.example.com" iSshPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSshTarget To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Authenticate to the target server (separate credentials).
    Get ComAuthenticatePw Of hoSshTarget "targetUser" sPassword To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSshTarget To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Connected to the target through the jump host."

    Send ComDisconnect To hoSshTarget
    Send ComDisconnect To hoSshJump


End_Procedure