Today I tried installing openwrt on my router to enable 'client mode wireless'.
Situation: I've several devices which do not have wifi capabilities. Moreover, it is physically not possible to connect them to the main router using cables. Consequently I wanted to convert an old router into a 'wireless client' which could then connect to the main router using a wifi bridge. All aforementioned devices would then simply connect with a cable to my wifi client router. In diagram format:
[device without wifi]->cable->[wifi client router]->wireless connection->[main router]->internet.
It turned out that this was a surprisingly complex task. First I tried setting up a WDS (Wireless Distribution System). Unfortunately, for reasons unknown to me, this just didn't work. Probably because my wifi client router running OpenWRT and my landlord's main router (different brand running OEM software) were not compatible.
Next I tried setting up OpenWRT in bridged client mode, but this didn't work either. My client router is a D-Link DSL-2740B with brcm63xx, and apparently openwrt bridge mode only works on brcm24.... (see bridgedclientmodeissues in openwrt wiki)
In the end I was able to setup a 'pseudobridge' using relayd. So far this seems to work well.
Digging a little deeper, there are some ways to make OpenWRT work in bridge mode using arpnat or ebtables, but this is not well supported: see "projectgus.com/2010/03/wireless-client-bridging-with-openwrt/"
Nowedays you can buy many cheap commercial network repeaters/extenders. I for instance recently bought the TPLink RE210. All I had to do was enter the main router's ssid+security information, tick the "client" box and voilla it worked. My question: how do these commercial repeaters work? Given the trouble I had with openwrt, there's probably not a trivial solution? Do these wifi extenders use trickery like arpnat/ebtables/relayd/...? Also, how would the performance of a commercial network repeater compare to openwrt+relayd (would you expect approximately comparable performance)?
ps. why on earth can't I put urls in my post? This is quite inconvenient...