Visual Basic 6.0

Connect to an SFTP Server Through a Jump Host

Demonstrates the Chilkat SFtp.ConnectThroughSsh method, which connects to an SFTP 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 hostname and port.

Background: This is the "jump host" (bastion) pattern: the application connects to a reachable gateway, then tunnels onward to an SFTP server that is only accessible from inside the network. Each hop authenticates separately with its own credentials. The result is a normal SFtp object — still requiring its own authentication and InitializeSftp — that happens to be routed through the first connection.

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Visual Basic 6.0

Dim success As Long
success = 0

'  Demonstrates the SFtp.ConnectThroughSsh method, which connects to an SFTP 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 hostname and port.

Dim sshJump As New ChilkatSsh

'  Connect and authenticate to the jump host first.
Dim port As Long
port = 22
success = sshJump.Connect("jump.example.com",port)
If (success = 0) Then
    Debug.Print sshJump.LastErrorText
    Exit Sub
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
password = "mySshPassword"

success = sshJump.AuthenticatePw("myJumpLogin",password)
If (success = 0) Then
    Debug.Print sshJump.LastErrorText
    Exit Sub
End If

'  Connect to the SFTP server through the jump host.
Dim sftp As New ChilkatSFtp
success = sftp.ConnectThroughSsh(sshJump,"sftp.internal.example.com",port)
If (success = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

'  Authenticate to the SFTP server (its own credentials), then initialize SFTP.
success = sftp.AuthenticatePw("mySshLogin",password)
If (success = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

success = sftp.InitializeSftp()
If (success = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

Debug.Print "Connected to the SFTP server through the jump host."

sftp.Disconnect 
sshJump.Disconnect