> The problem is the conflict that occurs naturally when connecting any two > ISPs.
in my not at all humble opinion, with this topology (each ISP presenting the same subnet on its client side), I would use multiple firewalls. One per ISP. Use carp if you want to failover or do fancy tricks (You can use multiple carps - one that represents going out firewall A, the other B, and they failover to each other. Much easier than editing every “LAN" boxes gateways otherwise.) fwiw, even if they have different subnets, I use one firewall per ISP. I learned the hard way - Crossing ISPs through the same firewall has generally seemed like path to losing sanity.
