Converting Linksys WRT54G to Wireless Bridge

We’ve been doing some repurposing of rooms the past week or two. In the process, an office got moved to the opposite side of the house from our FiOS modem. That office unfortunately is home to a circa 2005 Dell Workstation with no WiFi support.

Since I had an unused Linksys WRT54G router collecting dust, I spent a few minutes googling if I could use that to avoid stringing Cat5 down my hallway. Turns out with the help of some open source firmware (DD-WRT), you can do just that (and more).

The overall process is pretty straightforward – but as is common for this type of thing – lots of out-dated, inaccurate, or not fully defined documentation. So I thought I’d add to the mix ;)

What This Post Covers

Just so you don’t waste time readings this – this post specifically covers:

  • Linksys WRT54G ver 2.0
  • Installing DD-WRT firmware v24 SP2 [Beta] Build 13064
  • Configuring router as a Client Bridge
  • Issues using WPA2 security
  • Primary router is a Verizon FiOS ActionTec MI424WR-GEN2 (firmware version 20.19.8)
  • Date just for reference: March 2012

Bridge vs Repeater vs Yadda Yadda

I’m no expert in this area, so I took some time to get my bearings on what I actually needed to accomplish. There are lots of terms and setups, and overlaps between setups, but a bit of googling should set you straight.

In my case, I simply wanted to join a second LAN network over a wireless “bridge.” The second network would not provide wireless access, so the primary router is the only wireless access point for clients. So we want to setup our second router as a Client Bridge.

If you wish to also provide wireless access from the second router, I believe you want to configure it as a Repeater Bridge – which requires different instructions than I present here. More information on the different modes:

http://www.dd-wrt.com/wiki/index.php/Repeating_Mode_Comparisons

If any of this information is inaccurate, please let me know.

Installing DD-WRT firmware

DD-WRT is a Linux distribution which replaces the factory firmware, opening up lots of additional features for routers like the WRT54G. Since I only really cared about the bridge capability, I chose the micro binary. Wikipedia has a good overview of what each version supports:

http://en.wikipedia.org/wiki/DD-WRT

This video covers very simple and clear instructions on installing DD-WRT firmware onto the WRT54G (ver 2.0) – from downloading the binary to uploading the firmware onto the router:

http://www.youtube.com/watch?v=QZ_oW8-fmIA

I had no issues following these instructions – and were alot simpler than some other ones I came across. Once complete you should see the new DD-WRT admin console when you pull up 192.168.1.1 in your browser.

Configuring Router as a Client Bridge

Once you have DD-WRT up and running, we need to configure the router to act as a client bridge. The best instructions I found for this are here:

http://www.dd-wrt.com/wiki/index.php/Client_Bridged

These again worked (almost) without incident. If the primary router is configured for WPA2, things will likely not work from my experience and what I could find online. Luckily it’s very simple to isolate the issue to security. Disable security on both the primary router and your second router, then retry, and everything should work like a charm.

Using WPA2 Security

If your primary router is setup to use WPA2, and things didn’t work, you have a few options:

  • Drop to WEP security
  • Drop to WPA security
  • Enable WPA2 TKIP + AES support on primary router, WPA on secondary

Both WEP and WPA should work just fine between the DD-WRT and your primary router. I spent a good deal of time trying to find a way to maintain WPA2 on my network, and the only real solution was to enable mixed mode.

So configure your primary router to use WPA2 TKIP + AES, then set the DD-WRT to use normal WPA security. This worked for me without a hitch. I would assume this only reduces protection for the traffic over the bridge, while all traffic over the primary router should be using the more secure AES encryption. But I really don’t know enough about this stuff to say for sure.

Would love to know if this is accurate, or if enabling TKIP + AES reduces security overall.

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