can't get gdm greeter

[fboiteux at calistel.com (Frédéric BOITEUX)]

	Hello,

  I've digged a bit on my problem, and found that gdm starts when
I?give the '-ac' option to its X server, like this at the end of
gdm.conf :

[servers]
0=Standard -ac

The '-ac' Xserver option disables access control :

       -ac     disables host-based access control mechanisms.  Enables  access
               by  any host, and permits any host to modify the access control
               list.  Use with extreme caution.  This option exists  primarily
               for running test suites remotely.

So the problem come from access control... But I?don't find where :
- is it a xauth / xhost problem ?
- why the autologin gdm session works ?
- where can I fix the default config to be able to run the gdm greeter
instead of autologin ?

	any advice ?

	with regards,
		Fred.