The Linksys WRT54G has always been one of my favorite hacking targets. It’s a wireless 802.11b/g router that originally ran Linux as its OS. Later in life this was switched to non-open VxWorks. Linksys continued to produce a Linux compatible version of the router called the WRT54GL. I believe the one pictured above was originally a Fon purchased during the transition. When I first started playing with the WRT, it was to steal internet in a new apartment while I waited for my actual connection to be installed. I was using it in client bridge mode which means it would connect via WiFi to the remote access point and serve the connection to anything on the wired ports (one of which was another WRT).
I recently dug the router out because a friend is in a similar situation. I installed the latest version of DD-WRT and discovered that it has learned a new trick. In addition to ‘client’ and ‘client bridge’ mode bridge means the connection isn’t NAT’d DD-WRT now has ‘repeater’ and ‘repeater bridge’ mode. The router will attach to the access point of your choice and then rebroadcast the signal as the SSID of your choosing. You do this by setting up a virtual wireless interface. I followed these instructions for setting up a universal wireless repeater. The only problem I ran into was connecting to my Airport Extreme which uses WPA2… and AES (not TKIP) by default. It has been very hard to verify that fact though. Once I figured that out, it worked just as expected. I haven’t tested it outside of my apartment yet. Next up is putting DD-WRT on a new-in-box La Fonera; it’s slightly more involved than uploading new firmware to a web interface. I’ve done it before, but it’s just no fun.