WRT54G - Ethernet Bridge?

Discussion in 'Cisco/Linksys Wireless Routers' started by woogy12, May 3, 2005.

  1. woogy12

    woogy12 Guest

    Ive looked around here for an hour or so and cant seem to find the answer to my question:

    Is there anyway to configure (settiings or firmware) to make the WRT54G into an ethernet bridge such as WET54GS5?

    I currently have a cable modem connected to my WRT54GX on the third floor of my townehome. I have a spare WRT54G that I would like to put down in my garage and have it connect to my WRT54GX wirelessly. Then I want to be able to connect a couple desktops meachines via ethernet cable to the WRT54G and hopefully have internet access through the WRT54G --> WRT54GX --> cable modem.

    Any suggestions?

  2. dadaniel

    dadaniel Network Guru Member

    I'm also very interested in this settings if they exist.....
  3. davidsonf

    davidsonf Network Guru Member

    Sure. Any of the various 3rd party firmware packages will do it. They all have a "Client Mode", which allows the WRT54G to connect to an Access Point.

    The wireless connection is then bridged, just as it would be if it were acting as an Access Point itself, to the 4 LAN ports. The WLAN port is routed through the Linux kernel, which allows it to be passed through a firewall too.

    That's just the default configuration though! DD-WRT, and I'm not sure which of the others, will allow the bridge to be reconfigured. VLANs and I'm not sure what all (I don't use it, so I'm not really familiar with it).

    Basically, if you don't want to do anything more than you described, it's all sort of boring. If you want something special, like to be able to isolate some parts of your network from others... then it gets a lot more interesting.
  4. hotrat

    hotrat Network Guru Member

    There is a bit of a difference between client modes however.

    Client mode Routed and Client mode bridged

    Client mode routed won't allow you to see file shares on computers behind the Client router because the Client router AND Client PC's are on a different subnet ie AP .1.x .. Client router .2.x ...Client PC's .2.x
    and obviously being ip based is layer 3 routing.

    Client mode Bridge: all routers on the same subnet, allows you to have file sharing etc.

    basically ethernet switching. layer 2 based on MAC addressing.
    i still have not found a firmware where this works well, either restricted to 1 client pc behind the client router or problems with it working then seemingly clogging up and slowing to a crawl.

    NO idea how they do client mode bridging but it would be good if someone can explain it somewhere... like is it NAT of MAC addresses??? and why is it so troublesome??

  5. davidsonf

    davidsonf Network Guru Member

    That is just a configuration detail, not a limitation.

    I'm not sure what can be done with routing through the web interface (which I personally found very frustrating, and gave up on entirely). Subnetting can be on 16 bit boundaries, and that puts all of those in the same subnet, as opposed to 24 bit subnetting, which segregates them).

    I don't understand what problem you have exactly. The configuration you say doesn't work well is, near as I can tell almost identical to perhaps the most commonly used configuration for WRT54G units, and seems to work well for others (me included).

    I don't know that Client mode is any different as far as the bridge goes. They still connect the wireless and the four LAN ports directly to the bridge. The WLAN is multiplexed with a VLAN between that port and the ethernet interface to Linux. That same Linux port also multiplexes a VLAN connection to the bridged LAN/Wireless ports.

    I've never looked at this at the bit banging level, but it wouldn't be hard at all to change between AP and Client modes and see if the bridge and VLAN configuration is changed. I can't think of a reason why it would be.
  6. hotrat

    hotrat Network Guru Member

    Doesn't windows file sharing rely on broadcasts?? so yeah u can broadcast to .1.255 no probs but getting it to broadcast to .2.255 well how on main router and client router?? web interface won't let you..

    i don't quite understand what you mean by subnetting on 16bit boundaries... if you can explain i'd like to give it a try!!

    do you mean ??? or something else

  7. davidsonf

    davidsonf Network Guru Member

    I'm not familiar with it, and don't know the answer.

    Yes, that's it! If you use the web interface, all of the route commands are hidden (and are somewhat difficult to predict). But with any of the third party firmware packages you can either telnet into the router, or use the debug web interface to execute shell commands. Either way, you can see the actual route table, and change it if you want.

    Of course getting changes to be permanent is a great deal more complex, but that can be done too.

    What ever, the command "route -n" will dump the route table. The netmask column shows how each entry is applied to submasks. Hence if you have an entry with a netmask of (which is a 24 bit mask), that route will see a difference between 192.168.1.x and 192.168.2.x while a netmask of (a 16 bit mask) will see those as identical.
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