[PLUG] ssh tunnel's X11 display isn't showing up on remote machine...

[Russell Senior]

Okay, I am baffled.  I am ssh'ing into a remote machine (it happens to
be a Debian UML virtual machine) and for some reason I am getting
a null $DISPLAY when I get there.  This is despite /etc/ssh/ssh_config
setting "ForwardX11 yes" on the local side and /etc/ssh/sshd_config
setting "X11Forwarding yes" on the remote side.  My local $DISPLAY is 

  $ echo $DISPLAY           
  :0.0

but after ssh'ing in, at the remote end:

  $ echo $DISPLAY
  

On a working remote host, I see e.g.:

  $ echo $DISPLAY
  localhost:12.0

I've diff'd the sshd_config on a working versus not-working remote
hosts and they are identical.  Both sides are running OpenSSH
3.6.1p2-10.  

I just noticed that .Xauthority is empty on the non-working remote
host, whereas the working remote host's .Xauthority is non-empty.
Name resolution works in both directions.

WTF is the matter?

-- 
Russell Senior         ``With a heavy dose of fear and violence and a lot
seniorr at aracnet.com      of money for projects, I think we can convince
                         these people we are here to help them.''
                         Lt. Col. Nathan Sassaman (12/07/2003 Oregonian A13)