I was going through my archives the other day, and I found a thread that myself and user named hal9000 had around Dec 2003 talking about hosting your own servers. Here it is completely unedited:
The servers for UT DC were very nice server boxes, running winNT. Win2k and
XP *should* be able to run it as well, but I have not tested the server code
on anything other than NT. The box I ran my UT DC test server from was a
dual P3 600 box with 1 GB ram running Win NT4 sp3.
Sega's servers have sadly all been turned off. The server code for UT DC
was never released so it's not possible to set up your own server that way.
********A regular UT server will not recognize a Dreamcast client.********
that Infogrames ("Atari" now) or the programmers of UT DC could release the
server code, but not likely. The server code does not have features to
change the problems we had with -suicides crashing the server, chat spam,
lagging the server, etc. We were lucky to get a fix for the first big
problem with the "pause" command that came out long ago.
Another issue to be aware of, if you could get the UT DC server code, is
that there is an exploit for all old Unreal servers where people can crash
or compromise the server box running older versions of UT.