PureBasic

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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IncludeFile "CkSsh.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  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.

    sshJump.i = CkSsh::ckCreate()
    If sshJump.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Connect and authenticate to the first SSH server (the jump host).
    sshPort.i = 22
    success = CkSsh::ckConnect(sshJump,"jump.example.com",sshPort)
    If success = 0
        Debug CkSsh::ckLastErrorText(sshJump)
        CkSsh::ckDispose(sshJump)
        ProcedureReturn
    EndIf

    ;  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.
    password.s = "mySshPassword"

    success = CkSsh::ckAuthenticatePw(sshJump,"jumpUser",password)
    If success = 0
        Debug CkSsh::ckLastErrorText(sshJump)
        CkSsh::ckDispose(sshJump)
        ProcedureReturn
    EndIf

    ;  Connect to the target SSH server through the jump host.
    sshTarget.i = CkSsh::ckCreate()
    If sshTarget.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkSsh::ckConnectThroughSsh(sshTarget,sshJump,"target.example.com",sshPort)
    If success = 0
        Debug CkSsh::ckLastErrorText(sshTarget)
        CkSsh::ckDispose(sshJump)
        CkSsh::ckDispose(sshTarget)
        ProcedureReturn
    EndIf

    ;  Authenticate to the target server (separate credentials).
    success = CkSsh::ckAuthenticatePw(sshTarget,"targetUser",password)
    If success = 0
        Debug CkSsh::ckLastErrorText(sshTarget)
        CkSsh::ckDispose(sshJump)
        CkSsh::ckDispose(sshTarget)
        ProcedureReturn
    EndIf

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

    CkSsh::ckDisconnect(sshTarget)
    CkSsh::ckDisconnect(sshJump)


    CkSsh::ckDispose(sshJump)
    CkSsh::ckDispose(sshTarget)


    ProcedureReturn
EndProcedure