That's what happened. Immense lag. So much, that my server wouldn't even de-ping itself.

Anyway, problem solved. It didn't have to do as much with both JJ2s being open at the same time as my having forwarded my router. I forgot that I had recently rearranged my family's connections to the router. The result was that I was actually forwarding the ports to my mother's computer. I changed the forwarding back to the way it should be, and the server runs smoothly again.

BTW, does anyone know what ports I need to forward to be able to play UT online?