question about x11 forwarding in ssh
From: Andre Charbonneau (andre.charbonneau_at_nrc-cnrc.gc.ca)
Date: Wed, 21 Sep 2005 11:11:35 -0400 To: firstname.lastname@example.org
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
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?
-- Andre Charbonneau 100 Sussex Drive, Rm 2025 Research Computing Support, IMSB National Research Council Canada Ottawa, ON, Canada K1A 0R6