Starting with RHEL4, the system only accepts local (socket-based) X11 server connections. This means that if you go to another Unix server and try forwarding X11 output by using DISPLAY variable to point to your RHEL4 box, it will no longer work.

Enabling TCP connections to X11

In order to make your RHEL4 system accept TCP connections for X11, here’s what you need to do:

In /etc/X11/gdm/gdm.conf, uncomment the

#DisallowTCP=true

line and change it to

DisallowTCP=false

That’s it! Restart gdm and enjoy!

Different UNIX-like operating systems store information about their release versions differently. If you know what OS you have, but not sure about the version, then here’s how you can find out:

RedHat Linux

bash-3.1$ cat /etc/redhat-release
Red Hat Enterprise Linux Client release 5 (Tikanga)

Ubuntu Linux

bash-3.1$ cat /etc/issue
Ubuntu 6.10 n l

SUSE Linux

~> cat /etc/SuSE-release
SUSE Linux Enterprise Desktop 10 (x86_64)
VERSION = 10

Sun Solaris

bash-2.03$ cat /etc/release Solaris 8 2/04 s28s_hw4wos_05a SPARC Copyright 2004 Sun Microsystems, Inc. All Rights Reserved. Assembled 08 January 2004

See Also

• cat command
• check Raspbian version

H, and welcome to UNIX Tutorial – a future hub for all sorts of useful information on various UNIX systems.

The project is about to be launched by the end of August, so stay tuned! If you have any ideas/suggestions – please don’t hesitate to contact us immediately!