[gdm-list] strange XAUTHORITY setting

[jody <jody xha gmail com>]

HI
i am using GNOME 2.20.3 on a fc8 machine.

I recently noticed that instead of the default xauth file /home/jody/.Xauthority
the environment variable was set to /tmp/.gdmRI0JNV
(because of the name i assume this is somehing created by gdm)

the xauth file created by gdm is:

myhost.uzh.ch/unix:0  MIT-MAGIC-COOKIE-1  442fa938015fb6795c16e499cbe0097e
localhost.localdomain/unix:0  MIT-MAGIC-COOKIE-1
442fa938015fb6795c16e499cbe0097e
myhost.uzh.ch:0  MIT-MAGIC-COOKIE-1  442fa938015fb6795c16e499cbe0097e
myhost.uzh.ch:0  MIT-MAGIC-COOKIE-1  442fa938015fb6795c16e499cbe0097e
myhost.uzh.ch:0  MIT-MAGIC-COOKIE-1  442fa938015fb6795c16e499cbe0097e
localhost.localdomain:0  MIT-MAGIC-COOKIE-1  442fa938015fb6795c16e499cbe0097e

whereas the original one is simply:
myhost.uzh.ch/unix:10  MIT-MAGIC-COOKIE-1  2d7c230373fe5f2615f37027edf4d7c7


Is there a reason why this file is created and used?
I ran into problems with the gdm-created Xauthority file
 because with this file in use i can't use the DISPLAY variable
'myhost.uzh.ch:0.0'

Because i need a 'globally' valid DISPLAY variable to use
in a distributed application, i can't use ':0.0' .

So as a workaraound i just unset the $XAUTHORITY variable.
Is this safe?
Is there a way i can prevent the setting of the $XAUTHORITY variable
to the 'bad' value?

Thank You
  Jody