recreated it to http://www.tribes1.com
uhhhh... that looks like a Fan-Maintained site to me. That means that it's not an affiliate of sierra. It says right on there "site hosted and maintained by Conan"
As for the master server, it could be run on something as simple as a 486 linux box sitting in the bottom of a rack of other "old" machines. It's probably on a server computer of actual server class though, as they're designed to serve a hell of a lot more requests than a classic pentium II.
Anyhow... I'm getting off the tracks.
If tribes1 dies it'll suprise me. There are still people out there playing netmech, and that game is as old as earthsiege 2! (1995)
Adios!