I have an issue with routing.
I have 2 public subnets: 172.31.1.0/24 and 172.31.100.0/24
In each of these I have a NAT instance. Each NAT instance is an OpenSwan VPN peer to a remote location. This allows the following VPN connectivity:
172.31.1.0/24 -> 192.168.1.0/24 172.31.100.0/24 -> 192.168.100.0/24
I set up a single Route Table that is associated with both of my public subnets. this includes route entries as follows:
192.168.1.0/24 Target = NAT instance 1 192.168.100.0/24 Target = NAT instance 2
Everything works fine for the former, but no matter what I do, the route table entry for the later does not work.
No route that I setup for NAT Instance 2 works. When I traceroute to any address in 192.168.100.0/24, packets are sent directly to 192.168.100.0/24 (and therefore fail) rather than routing via NAT Instance 2.
I thought maybe there was a limit on the number of concurrent NAT instances in a Route Table, but even when I delete the route to 192.168.1.0, so that the only route that exists is the route via NAT instance 2, it still doesn't work.
I've checked all the usual stuff (Src/Dst check etc) but nothing seems to be out of place. All of this was created with CloudFormation, so manual error isn't likely.