I have set up dual WAN, fed from two different Modems. WAN1 is the fastest connection, and is marked as primary WAN. WAN2 is deemed backup. The internet load balancing and link backup is working as expected and is great.

Now comes the issue.

app1 DNS is the IP of WAN1. It has a NAT on a few different ports that translate to some servers internally.

app2 DNS is the IP of WAN2. It has a NAT on a few different ports that translate to some servers internally.

Only one of these will work at a time. If app1 is working, externally, then app2 is not, and vice versa. I'm not positive what makes them swap, but it's incredibly annoying. If I make all apps go to one of the WAN IPs, and NAT from that, all works fine.

I've tried disabling Application Optimized Routing:, didn't fix it. I've tried without Link Backup, no go. I've tried with Link Backup - no go.

I've tried creating policy routing to make the one server always go out the WAN IP that it's NATed from, and the other to the other WAN, still no go.

There MUST be something obvious I'm missing. Can I not have different WANs NATing to different local addresses?

I appreciate any help anyone can offer. As to the well, why are you doing this? My primary is the strongest speeds. I'm having all my gaming servers/apps like teamspeak run through this. I want all my generic external web hosting and camera software to go through the weaker link. I have priorities - haha.

I'm using the default attack prevention settings.