NAT Router and DSL Modem Static Routing
October 31, 2007
So you have a DSL or Cable modem and you can't access the modem interface because your computer is wirelessly connected to a router and the router is connected to the modem? The only trick is to get up, go unplug the cable from the router and plug in your computer directly into the modem? If your router has decent firmware, the answer is NO!.
In this article we can solve the issue of getting to the DSL modem from behind a router using something called a static route. In my network, my router is set to 192.168.1.1 on the wireless interface while my modem is set to 192.168.0.1 on the wired WAN interface. That means when I point my browser to 192.168.0.1 to try to access the modem, it does not work because the router thinks I am looking for a computer on the wireless network. The trick is to get the router to catch the 192.168.0.1 packet and route them to the WAN interface which is connected to the modem.
If you're like me, you will have bought a DD-WRT firmware compatible router and flashed your router to DD-WRT firmware. This gives us much better control over the router and much stabler software so the router does not crash as often.
To setup a static route to the modem in DD-WRT, all you need to do is connect to the router's web interface (typically http://192.168.1.1) and click on "Setup" tab followed by the "Advanced Routing" tab. In the advanced routing page, there is a static routing section. Select a set number (1 is the first so I use that) and type "dslmodem" as the "route name". For the "Destination LAN IP" enter your modem's access IP (mine is 192.168.0.1). For "Subnet Mask" enter 255.255.255.0 and leave "Gateway" as 0.0.0.0. Finally change the "Interface" to WAN and click "Save Settings".
To test it out, try accessing your modem's ip (mine is http://192.168.0.1) and your modem's configuration page should pop up! No more disconnecting wires to get to the modem configuration!