Home Networking - Dual Routers?

Factual Questions
1

I currently have a home network using a Linksys WRT54G router/switch. I have a couple of spare Linksys BEFSR41 router/switches. The older ones work just fine.

I would like to experiment by installing some open source firmware. Is it possible to use a switch between the cable modem and the separate router/switches so that my wife can continue to be connected to the Internet via one of the older router/switches while I use the wireless router/switch to install DD-WRT or Tomato firmware?

Mind you this would not be a permanent arrangement, but just long enough to get it working. I want a fallback just in case it doesn’t work.

2

You can’t put a switch between the two routers because the cable modem will only give out one IP Address. However, you should be able to hook the old router up to the cable modem, and attach the WAN port of the router with the experimental firmware to one of the LAN ports of the old router.

3

That may not have been clear. Here’s the arrangement I’m talking about:


                    Cable Modem
                         |
            --------------------------
            |         WAN Port       |
            |        Old Router      |
            |        LAN Ports       |
            --------------------------
                 |              |
       -----------              ----------
       |                                 |
     Wife's                              |
    Computer                 ---------------------------
                             |         WAN Port        |
                             |Router With Open Firmware|
                             |        LAN Ports        |
                             ---------------------------

If you use this setup, it’s critical that the network on the old router is a different subnet from the network on the open firmware router. If the previous is total gibberish to you, here’s what you need to do: (hopefully) your router is configured to give out IP Addresses with DHCP. The usual default is to give out addresses on 192.168.1.x. At least one of the first three digits need to be different on the second network provided by the open firmware. There are rules on what IP Address ranges you’re allowed to use for your own private network(breaking these rules could cause you all kinds of problems trying to connect to the internet). My suggestion is to have the old router give out IP addresses on 192.168.1.x and the open firmware router give out IP addresses on 192.168.2.x.

If the networks are both wireless, then you need to do the above and make sure that the SSID for the two wireless networks is different.

4

Lots of good advice there but I’ll take issue with this one: it will be very helpful when problem-solving for the difference to be immediately obvious, so I would not use a 192.168.x.x address for the open firmware router but a 172.16.x.x or 10.x.x.x address.

5

:smack: I knew that.

At least I only solicited the advice late in the day and did not begin the actual process. What plan to do is download all the firmware first, then use a spare laptop connected only to the router (which will not be connected to the network) to update the router. Once that seems to be working properly, I will actually connect to the network using your diagram for further testing.

And thanks Quartz for the additional tip.