troubles with GDM and XDMCP

[Andrew]

Hello all,

I've a workstation that I'd like to use as a terminal server for several
laptops. All are running FreeBSD 6, GNOME 2.12, and GDM. XDMCP is
enabled on the workstation, but I'm not able to login (remotely) with
any of the latops. If I run XDMCP chooser from GDM, it times out saying
that it cannot find any available hosts on the local network. sockstat
shows that gdm is in fact listening on the workstation; however the
strange bit is that sockstat shows a udp6 connection. I have ipv6
disabled in rc.conf on both workstation and laptops. All traffic between
the workstation and laptops is going through a wireless gateway, and I
am wondering if perhaps the gateway does not handle ipv6. 

So I suppose my questions are: Why is gdm listening on a upd6 socket?
Does this imply that gdm is able to _make_ requests via ipv6? Anyone
else have something similar set up?

By the way, I really would like to do this with XDMCP, instead of via
SSH, or VNC, etc for the simple reason that I'm not sure I could live
without virtual desktops in GNOME :-). 

Thanks for any pointers/advice...

-Andrew