B4X

Request SSH X11 Forwarding

Demonstrates the Chilkat Ssh.SendReqX11Forwarding method, which sends an X11-forwarding request on a session channel. The arguments are the channel number, whether forwarding is limited to a single connection, and the X11 authentication protocol, cookie, and screen number.

Background: X11 forwarding lets a graphical program running on the remote host display its window on your local machine, tunneled over SSH. This is a low-level method that only sends the protocol request — your application is still responsible for the local X server side of the arrangement. The authentication cookie guards the forwarded display, so it should be a freshly generated value rather than a fixed constant.

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Dim success As Boolean = False

'  Demonstrates the Ssh.SendReqX11Forwarding method, which sends an SSH X11-forwarding request
'  on a session channel.  The 1st argument is the channel number, the 2nd limits forwarding to a
'  single connection, and the 3rd through 5th supply the X11 authentication protocol, cookie,
'  and screen number.

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

Dim sshPort As Int = 22
success = ssh.Connect("ssh.example.com", sshPort)
If success = False Then
    Log(ssh.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 = ssh.AuthenticatePw("mySshLogin", password)
If success = False Then
    Log(ssh.LastErrorText)
    Return
End If


'  Open a session channel.  A negative return value indicates failure.
Dim channelNum As Int = ssh.OpenSessionChannel
If channelNum < 0 Then
    Log(ssh.LastErrorText)
    Return
End If


'  Request X11 forwarding.  Named variables make each argument's meaning clear.
Dim singleConnection As Boolean = False
Dim authProt As String = "MIT-MAGIC-COOKIE-1"
Dim authCookie As String = "d92f5e1a7c8b4306af17c2e5b9d43081"
Dim screenNum As Int = 0
success = ssh.SendReqX11Forwarding(channelNum, singleConnection, authProt, authCookie, screenNum)
If success = False Then
    Log(ssh.LastErrorText)
    Return
End If

Log("X11 forwarding requested.")

ssh.Disconnect