The last time I tried to get jabberd set up on an Ubuntu install, the port-opening and config became a nightmare and induced me to give up. No good signal on why it wasn't working.
oh interesting, fair enough; I didn't know jabberd still existed! FWIW, Prosody, Ejabberd, OpenFire, etc. all mostly have sane defaults for a basic chat system (both in terms of performance and features). They won't be an exact match of course, but all the basic stuff should be there.