I have a linux box (Redhat 5) running xdm.
When I log in from a Win 95 xserver, the xlogin window shows the hostname as '1' instead of its correct name.
I believe the name is supposed to come from the file etc/X11/xdm/Xresources, where the line
xlogin*greeting: CLIENTHOST appears - I believe this is supposed to be replaced with the correct line by Xsetup.
As far as I can tell, other files appear to be correct.