B4X

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.

Chilkat B4X Downloads

Download Chilkat for B4X

B4X

Dim success As Boolean = False

'  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.

Dim sshJump As ChilkatSsh
sshJump.Initialize("sshJump")

'  Connect and authenticate to the first SSH server (the jump host).
Dim sshPort As Int = 22
success = sshJump.Connect("jump.example.com", sshPort)
If success = False Then
    Log(sshJump.LastErrorText)
    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.
Dim password As String = "mySshPassword"

success = sshJump.AuthenticatePw("jumpUser", password)
If success = False Then
    Log(sshJump.LastErrorText)
    Return
End If


'  Connect to the target SSH server through the jump host.
Dim sshTarget As ChilkatSsh
sshTarget.Initialize("sshTarget")
success = sshTarget.ConnectThroughSsh(sshJump, "target.example.com", sshPort)
If success = False Then
    Log(sshTarget.LastErrorText)
    Return
End If


'  Authenticate to the target server (separate credentials).
success = sshTarget.AuthenticatePw("targetUser", password)
If success = False Then
    Log(sshTarget.LastErrorText)
    Return
End If

Log("Connected to the target through the jump host.")

sshTarget.Disconnect
sshJump.Disconnect