LAN Question

Bills are high, customers aren't paying on time, Tranny in truck was just replaced, but I hooked up the network and played MP with my son.....LIFE IS GOOD
Question: Being somewhat new to LANs, I'm having trouble with QuakeIII in multiplyaer. I'm serving okay, but both my Son's and my Wife's computers are going through the modems even though they are both set for Local and LAN connections. After canceling the dial ups, they both enter and play fine. What am I mssing? Also can't get UT to connect at all. We also play Delta Force and it runs fine.
Running Netgear hub with FA310TX cards, but wife's has a built in card.
1(server)- P3 800, Abit BE-6II, 256MB (Win98 1st)
2-(Wife's) Duron 750 with a Amptron K7-810LMR, 128MB (98 1st)
3-(Da boy's) P2 333 512K, Soyo 6BA-III, 128 MB (98 2nd)
Need other info?