Karmic Koala (Ubuntu): enable remote x clients through TCP

It seems every version of Ubuntu has a different way to enable remote connections to the local X server.

I'm asking this question, while I do my own research: how can I enable the X server listening to TCP port 6000 on my machine, thus allowing remote X clients to connect to said port and use my display?

From serverfault ΤΖΩΤΖΙΟΥ

• Based on information found in this page about enabling XDCMP and the file /etc/gdm/gdm.schemas, I managed to create the following file:

  # /etc/gdm/custom.conf
  [xdmcp]
  
  [chooser]
  
  [security]
  DisallowTCP=false
  
  [debug]
  

  I also changed the /etc/X11/xinit/xserverrc file to:

  exec /usr/bin/X11/X
  

  i.e. I removed the -nolisten tcp options to the X executable. I don't know if I needed to. You might want to try avoiding this edit.

  After that, all that is needed is a restart of the gdm process:

  sudo service gdm restart
  

  You can verify the success as:

  tzot@tzot-laptop:/etc/X11
  $ netstat -an | grep -F 6000
  tcp        0      0 0.0.0.0:6000            0.0.0.0:*               LISTEN
  tcp6       0      0 :::6000                 :::*                    LISTEN
  

  From ΤΖΩΤΖΙΟΥ

• Of course, it's more convenient and secure to use ssh's X forwarding, so I assume there's some pressing reason not to do that...

  ssh -X destination

  ΤΖΩΤΖΙΟΥ : Yes: a 500 MHz Geode LX processor in the other side of the secure local network doing already too much for the 5 watts it requires, whose hardware AES module is not being used by OpenSSL on linux; no way to open an SSH connection with *no* encryption at all; no reason to spare a couple megabytes of the non-upgradeable 256 MiB of said server for an otherwise unneeded SSH process. Your intentions were good, but I really meant my question as-is; your answer is currently not helpful, and should probably be a comment to my question.
  From rescdsk

• if found it in /etc/gdm/gdm.schemas

  converted true to false, now it works

  <schema>
    <key>security/DisallowTCP</key>
    <signature>b</signature>
    <default>false</default>
  </schema>
  

  http://supermanhelp.com

  From $pageUsers[$post.author].name

• Yes, there is a pressing reason for me, x2x is a great tool for two connected computers on a lan.

  From $pageUsers[$post.author].name