PowerBuilder

Connect an SSH Tunnel Through a Jump Host

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

Background: This chains the tunnel through a "jump host" (bastion): the application reaches a gateway server, then tunnels onward to an SSH server that is only accessible from inside the network. Each hop authenticates separately with its own credentials. The result is a normal SshTunnel — still requiring its own authentication and BeginAccepting — whose transport is routed through the first connection.

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integer li_rc
integer li_Success
oleobject loo_SshJump
integer li_SshPort
string ls_Password
oleobject loo_Tunnel
integer li_WaitForThreadExit

li_Success = 0

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

loo_SshJump = create oleobject
li_rc = loo_SshJump.ConnectToNewObject("Chilkat.Ssh")
if li_rc < 0 then
    destroy loo_SshJump
    MessageBox("Error","Connecting to COM object failed")
    return
end if

//  Connect and authenticate to the jump host first.
li_SshPort = 22
li_Success = loo_SshJump.Connect("jump.example.com",li_SshPort)
if li_Success = 0 then
    Write-Debug loo_SshJump.LastErrorText
    destroy loo_SshJump
    return
end if

//  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.
ls_Password = "mySshPassword"

li_Success = loo_SshJump.AuthenticatePw("myJumpLogin",ls_Password)
if li_Success = 0 then
    Write-Debug loo_SshJump.LastErrorText
    destroy loo_SshJump
    return
end if

//  Set up the tunnel and connect to the target SSH server through the jump host.
loo_Tunnel = create oleobject
li_rc = loo_Tunnel.ConnectToNewObject("Chilkat.SshTunnel")

loo_Tunnel.DestHostname = "db.internal.example.com"
loo_Tunnel.DestPort = 5432

li_Success = loo_Tunnel.ConnectThroughSsh(loo_SshJump,"ssh.internal.example.com",li_SshPort)
if li_Success = 0 then
    Write-Debug loo_Tunnel.LastErrorText
    destroy loo_SshJump
    destroy loo_Tunnel
    return
end if

//  Authenticate to the target SSH server (its own credentials).
li_Success = loo_Tunnel.AuthenticatePw("mySshLogin",ls_Password)
if li_Success = 0 then
    Write-Debug loo_Tunnel.LastErrorText
    destroy loo_SshJump
    destroy loo_Tunnel
    return
end if

//  After authenticating, call BeginAccepting to start listening for local connections to forward.

li_WaitForThreadExit = 1
li_Success = loo_Tunnel.CloseTunnel(li_WaitForThreadExit)
if li_Success = 0 then
    Write-Debug loo_Tunnel.LastErrorText
    destroy loo_SshJump
    destroy loo_Tunnel
    return
end if

loo_SshJump.Disconnect()


destroy loo_SshJump
destroy loo_Tunnel