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Network Security Secure-Shell
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RE: Some servers do not forward X11, but I do not know why.

Subject: RE: Some servers do not forward X11, but I do not know why.
Date: Fri, 9 Dec 2005 10:14:45 -0700
Interesting...

Do you have lsof available on the hosts where you can't get X
forwarding?  lsof -i should tell you all the processes with ports open,
you can verify if there is some process hogging all 999 ports...

If not, some versions of netstat can also show you the PID of the
process that has the socket open.

Regards
Mark

-----Original Message-----
From: Christopher L. Barnard [mailto:cbar44@tsg.cbot.com] 
Sent: December 8, 2005 13:23
To: secureshell@securityfocus.com
Cc: Christopher L. Barnard
Subject: Re: Some servers do not forward X11, but I do not know why.


On 12/6/05, Christopher L. Barnard <cbar44@tsg.cbot.com> wrote:

I have two identical Sun Solaris 9 servers.  Both are running OpenSsh 
version 4.2p1.  Both have identical ssh_config and sshd_config files.

One allows me to run X programs and they are displayed back on my
desktop.
The other one reports

Error: Can't open display:

What am I missing to force this server to set the DISPLAY variable so 
that
X11 will be forwarded?  As I say the ssh_config and sshd_config files 
are identical with a server that works, and in particular ssh_config:

ForwardX11 yes

and sshd_config:

X11Forwarding yes
X11UseLocalhost no


To add some information:
not only is xhost not used, the binary is deleted if it exists every
night on all servers by cron.  Xhost is Evil (tm).

Xauth is not the issue.  It is in the same place on all servers.

I have figured out what the problem is, but not how to solve it.
Running the daemon in 3-layer-deep debug mode (-ddd) I discovered that
the reason the server is responding "Error: Can't open display:" is

debug2: bind port 6260: Address already in use

repeated 999 times, for the 999 ports from port 6000 to port 6999.  Then
the two messages Failed to allocate internet-domain X11 display socket.
debug1: x11_create_display_inet failed.

I am ssh-ed in, but I do not have X.

The server is busy, with about 200 ssh connections to it, but nowhere
near the 999 maximum X tunnelling number...

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| Christopher L. Barnard         O     When I was a boy I was told that
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