I'm using Mandrake 8.1, but have a Mandrake 8.0 in another partition (same PC). Mandrake 8.0 has xdmcp working perfectly but I cannot get it working on the 8.1 even having copied /etc/X11/ directory from 8.0 to 8.1.
Well, actually I cannot remotely connect to X (xdmcp) when using gdm manager. If I launch xdm instead it does work, thougth will not prompt for a WM or environment only booting into IceWM. (I need KDE in remote ;-)

Error message (ethereal protocol analysis) is 'Display not authorized to connect', but I think configuration is OK!!!! I attach only the relevant part of config files that I think are the keys:

/etc/X11/xdm/Xaccess
...
* #any host can get a login window
...
...
[servers]
0=/usr/bin/X11/X

[xdmcp]
Enable=true
HonorIndirect=true
MaxPending=4
MaxPendingIndirect=4
MaxSessions=16
MaxWait=30
MaxWaitIndirect=30
Port=177
PingInterval=5
DisplaysPerHost=2
Willing=/etc/X11/gdm/Xwilling
...

Note:
1º) I don't have a /etc/X11/gdm/Xwilling file (if it is needed, how to get/make one?)
2º) XDMCP is running according to lsof command, but 'nmap -sT -O localhost' does not show it !!


Please, can anyone tell me what am I missing?? Thanx a lot for your time and interest reading this ;-))