I have two routers: router A with internet access (DSL cable), and router B acting as a client connected to router A via wifi. Devices are attached to router B via ethernet.

I need to forward some ports to PCs attached to router B. I've set a static route to router B, but router A won't let me forward ports to a different subnet.

What can I do?

I tried to make everything belong to a single subnet with 2 DHCP servers with separate ranges, but it won't work, I think because the static route destination is inside router A subnet.

Shall I use double NAT? Are there other viable solutions?

  • Why not have router A forward to router B's IP, and router B forward to the attached PC? It's a little cumbersome doing two port forward configurations, but it works fine. – jdh Feb 9 '15 at 19:09
  • Isn't this double NAT? – InfiniteSnow Feb 9 '15 at 19:11
  • Does your either router have a bridge mode? If you make it a bridge, then you don't have to worry about router A and B scenario. You just have one router and port forwarding will be easier. That's how do it to bridge the upstairs cable modem/router combo with a WRT54GL (Tomato) downstairs. I have in bridge mode to repeat the cable modem upstairs. – Sun Feb 9 '15 at 19:19
  • No bridge mode unfortunately :( – InfiniteSnow Feb 9 '15 at 20:39

If router B is a WiFi client connected to router A, then you do not need routing or DHCP enabled on router B at all. The wireless connection should be equivalent to you connecting an ethernet cable from one of Router B's LAN ports to one of Router A's LAN ports.

Systems connected to router B via ethernet will pull IPs and other information from Router A's DHCP server.

You should just set router B's IP address to a static IP on router A's subnet "out of the way" (outside of Router A's DHCP scope).

I have a working setup like this with a DD-WRT router acting as a client to an Asus AP.

This is assuming both your routers do not have any weird VLAN setup. If you have problems, disable any unneeded VLAN functionality. Multiple SSID functionality may also interfere.

  • The problem is that I need the DHCP server on router B because it has additional functionality like PXE. – InfiniteSnow Feb 9 '15 at 20:42
  • THen kill the DHCP on A. – LawrenceC Feb 9 '15 at 22:57
  • The point is to have one (non-redundant) DHCP server per subnet - so if everything is on the same subnet logically it doesn't matter where the the DHCP server is physically. – LawrenceC Feb 9 '15 at 23:09

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