Simple question: How to make X windows appear on remote machine (not X forwarding)

[Dan Kegel]

On Tue, Apr 15, 2008 at 11:27 AM, Dustin Spicuzza
<dustin at virtualroadside.com> wrote:
>  I have a machine sitting next to me that I ssh into, logged in as user
>  Y. On the machine, I have X running, and I'm logged in as the same user
>  Y. Is it possible to execute an application over ssh, that makes its
>  windows show up on the machine next to me? I tried setting the $DISPLAY
>  variable, but no luck so far. Thanks.

Make sure X is listening on tcp, too.  Modern desktops
tend to start X with the -nolistentcp option.  See e.g.
/etc/gdm/gdm.conf, which says

# If true this will basically append -nolisten tcp to every X command line, a
# good default to have (why is this a "negative" setting? because if it is
# false, you could still not allow it by setting command line of any particular
# server).  It's probably better to ship with this on since most users will not
# need this and it's more of a security risk then anything else.
# Note: Anytime we find a -query or -indirect on the command line we do not add
# a "-nolisten tcp", as then the query just wouldn't work, so this setting only
# affects truly local sessions.
DisallowTCP=true

See also
http://groups.google.com/group/comp.os.linux.x/msg/05b9b324bb91bb29
- Dan