> # Set up nat on institute interface
> iptables -t NAT -A POSTROUTING -o lan1 -j SNAT --to 10.2.0.41

root@triss:~# iptables -t NAT -L
iptables v1.4.4: can't initialize iptables table `NAT': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
root@triss:~#

Ни на какие мысли не наводит?