I am testing a redundant internet connection setup that works like this -
I have a network segment, 192.168.80.X It has two gateways - 192.168.80.1 - a FW connected to a frame relay line 192.168.80.2 - an ADSL modem/router
I set up a windows server with a static ip 192.168.80.10, subnet 255.255.255.0 and two default gateways - 192.168.80.1, 192.168.80.2 and set the metrics manually to give the frame relay line preference.
Both routers have port forwarding set up to forward port 80 from the WAN address to the server.
The problem is that when the default gateway selected by windows is 192.168.80.1, it won't accept incoming connections coming from the ADSL router, and vice-versa - if the gateway selected is 80.2 then connections coming to the WAN address of the FW don't get through.
Is this kind of setup even theoretically possible? If it is, I assume it's a routing issue that needs solving? Perhaps adding a route manually to the server/WAN routers?
I'm not networking-savvy enough to figure it out on my own.. some help will be appreciated.