Hi,
I'm having a couple of issues trying to setup a dual isp configuration on a linux firewall, with the intention of separating some services and configuring redundancy into others in the future.
I've 3 nics configured eth0 - ISP0, eth1 - ISP1, eth2 - Lan and used the guide in the LARTC to configure multiple uplinks and providers to modify the default gateway depending upon interface used.
Also configured SNAT for traffic leaving each of the ISP interfaces and a few DNAT entries to test port fowarding access over each provider.
The above configuration seems to work fine for connections directly to the firewall whichever isp they come in from but not for traffic that connects through the non-default interface ie SMTP/RDP etc.
If I change the preferred default interface to the secondary ISP only sessions initiated via that provider connect.
Is this going to be achievable with Linux & iptables or will I have to go for a multi firewall setup?
thanks,
Martin.
