question about x11 forwarding in ssh

From: Andre Charbonneau (andre.charbonneau_at_nrc-cnrc.gc.ca)
Date: 09/21/05

  • Next message: Darren Tucker: "Re: question about x11 forwarding in ssh"
    Date: Wed, 21 Sep 2005 11:11:35 -0400
    To: secureshell@securityfocus.com
    
    

    Hi,
    I'm currently trying to debug a SSH client implementation library which
    tries to do x11 forwarding. In the code it tries to open a socket to
    localhost:6000 when a x11 channel request arrives (on the ssh client
    side). But I get a 'connection refused'. I checked my system
    configurations and indeed my xserver is started with "-nolisten tcp", so
    this explains why I can't connect to port 6000.

    But I've read somewhere that someone should only open port 6000 only if
    they really really need it, and that they should use ssh x11 forwarding
    instead.

    But my question is: How does the SSH client (openSSH for example)
    forwards x11 when port 6000 is not open??? Does it use another, special
    port that it can connect to?
    Is there a document online that I can read that explains in details how
    ssh does the x11 forwarding?

    Thanks!
        Andre

    -- 
    Andre Charbonneau
    100 Sussex Drive, Rm 2025
    Research Computing Support, IMSB
    National Research Council Canada
    Ottawa, ON, Canada K1A 0R6
    

  • Next message: Darren Tucker: "Re: question about x11 forwarding in ssh"