I am in the process for setting up a fairly complex firewall, that has 5 nic's 
in it. (one build on + 4port Dlink card) The basic setup is going to be the 
office on one, Charter Cable on one, Astound Cable on one, and our wireless 
gateway on the other (the wireless gateway is a Linksys WAP+router+4 port 
switch).  We dont need to load balance the internet connections, but I need 
to be able to freely switch the default gateway between the two (and we may 
be adding a 3rd soon too) 

Can I have some suggestions on how to configure this? Both iptables rules and 
generic policies would be great. Right now I have a very basic setup, but I 
know there are some problems with it (being able to route between the 
external interfaces, and the WAP without much security to name a few) Most of 
the firewall solutions out there only work for single internet connections, 
so I will have to do most of this by hand, I assume.

Jay