Norton Internet Security 2005 seems to have no way to open port 113 (auth). Evem though I explicitly open it in the personal firewall options, with a packet sniffer I can see the incoming packets arrive at the PC only to disappear without a trace. A google search reveals that NIS 2005 (possibly) has some kind of worm detection feature responsible for this behaviour but I can't find it.
Any clues? (H/W is a PC running XP Pror)