Comment 13 for bug 58071

I bumped into this bug - actually https://bugs.launchpad.net/ubuntu/+source/gdm/+bug/105938 (marked as a dup of this).

I found a workaround - which I document here for others.

The problem is not xdmcp - the problem is a failing dns lookup of the hostname of the machine.

I configured dnsmasq on the gdm machine, named myhost.org

In /etc/dnsmasq.conf I added this :-

local=/myhost.org/

That forces any lookups in that domain to come from /etc/hosts

xdmcp magically started working again. Just this change.