D6200 Not performing network address translation

[BMorris93]

Hello,

I have just implemented a D6200 router into my home network and I am having an issue where it does not seem to be applying NAT and modifying the layer 3 information of my traffic.

My network is simple, I have 2 subnets in use, the 192.168.0.0/24 & 10.100.10.0/24. My client connects to a switch and then into my PA-200 firewall. The firewall then routes traffic up to the netgear router.

When I connect to the Wi-Fi radios on the router then I get assigned an address from the router and everything works fine as expected.

The firewall is the default gateway for the 10.100.10.0/24 network. I have a default static route in place to route traffic out another interface on the firewall to 192.168.0.1/24 (IP address of the D6200 router).

I then have a static route in place on the netgear router to forward 10.100.10.0/24 traffic down to 192.168.0.2/24 (the layer 3 interface on the firewall) and the firewall sends it back to my client.

This works fine, I can easily access the upstream netgear GUI and ping it as expected.

However if I try and access anything past the router, I am unable to. I do not recieve a response from google's public DNS server of 8.8.8.8 when I try to ping this. The routes and are all in place on the router's routing table and traffic is correctly NAT'd when I connect directly to the router via the wireless connection.

I am seeing in the statistics that traffic is being transmitted but none recieved when I send traffic via the 10.100.10.0/24 network. I have yet to confirm with my ISP that they are recieving private IP address traffic, however I strongly suspect that what is happening is that traffic from this subnet is not having NAT applied so the router is forwarding out private IP traffic to the ISP which is then dropping it as expected in this situation.

Has anyone had a similar experience? Does anyone know if there is a resolution for this issue or is it a case of having to switch back to my old router? It seems that the behaviour is that the router only applies NAT on the subnet that is it in.

[TheEther]

I suspect you are correct in that the Netgear doesn't know how to NAT traffic from 10.100.10.0/24.  Maybe you can enable RIP on the PA-200 and D6200 and see if that makes any difference.  Honestly, I doubt it will help.

Another option is to configure the PA-200 to use a more specific subnet, say 192.168.0.128/25.  Configure static route 192.168.0.128/255.255.255.128 to 192.168.0.2 on the D6200.  You have to make sure the DHCP pool on the D6200 has an ending address no higher than 192.168.0.127 to avoid overlapping the more specific subnet.

Then, any traffic from the firewall's subnet will appear to the D6200 to be part of 192.168.0.0/24 and should be properly NAT'd.

[BMorris93]

I've tried using a different subnet but this has had no effect. The router is not fit for purpose, I'll have to take it back and use my old ISPs one.