Following up on . As some may recall, my problem was that I was unable to connect to a SonicWall VPN where my LAN traffic was routed through a simple NAT box running iptables.
Wolfgang Kueter suggested in this forum that the problem was that NAT-T is 'crap' and that I was 'clueless.'
As it turns out, a kernel upgrade to 2.6.15.1 seems to have fixed the problem.