Hi, Sorry for posting again, but I must have been asking the wrong question. How do I get a bridge with an ethernet and a wireless interface to work? I see many HOWTOs on the internet using brctl and ifconfig doing what I would do with two ethernet interfaces, but I simply have not been successful using my wireless interface with the ipw3945 driver. Is that because of the hardware+driver or is there some magic I'm missing (apart from parprouted or iptables, which does work but is not what I want) ? http://www.linux-foundation.org/en/Net:Bridge#It_doesn.27t_work_with_my_Wireless_card.21 tells me to expect this. It says:> FAQ 7.16: It doesn't work with my Wireless card! > > This is a known problem, and it is not caused by the bridge code. > Many wireless cards don't allow spoofing of the source address. It is > a firmware restriction with some chipsets. You might find some > information in the bridge mailing list archives to help.... HELP! Are the HOWTOs wrong, or is the above FAQ info wrong? What cards can I buy that are not part of "many wireless cards"? I prefer USB hardware but I don't know what to buy. I got two responses to my last post: https://lists.linux-foundation.org/pipermail/bridge/2008-April/005797.html One to use brctl (which doesn't work for me!) and one to run my linux bridge under VMware on a windows host (which is not what I want). I'm wondering about the lack of answers. Am I asking a stupid question? Is there any obvious reading I haven't done? Even an answer like "Forget it. You'll never get a ethernet/wireless bridge to work under Linux. The FAQ should be changed from 'many' to 'all'." would also be helpful, as I would stop trying and stop posting! :D Peter -- Peter Valdemar M?rch http://www.morch.com
On Mon, Apr 28, 2008 at 11:25:07AM +0200, "Peter Valdemar M?rch (Lists)" wrote:> http://www.linux-foundation.org/en/Net:Bridge#It_doesn.27t_work_with_my_Wireless_card.21 > tells me to expect this. > > It says: > > FAQ 7.16: It doesn't work with my Wireless card! > > > > This is a known problem, and it is not caused by the bridge code. > > Many wireless cards don't allow spoofing of the source address. It is > > a firmware restriction with some chipsets. You might find some > > information in the bridge mailing list archives to help. > > ... HELP! Are the HOWTOs wrong, or is the above FAQ info wrong?Spoofing the source MAC is actually forbidden by the 802.11 standard. Bridging between ethernet and wireless is really only possible if either your host is an access point or you are using a WDS interface (or both). The upstream mac80211 code does not currently support being an access point (although there are patches floating around that enable it). IIRC, a patch to enable using WDS has recently been merged. Whether or not that is useful depends on what equipment you have, and honestly I haven't really used it myself. What is the goal you are trying to achieve? In many cases it might be easier for you to simply setup NAT routing between your ethernet and wireless connections. John -- John W. Linville linville at tuxdriver.com
John W. Linville a ?crit :> > Spoofing the source MAC is actually forbidden by the 802.11 standard.My two cents : We all agree about the fact that most current wireless implementations do not permit spoofing the source MAC, probably for many good and several bad reasons. But wouldn't it be possible, as a temporary and dirty fix, to simply send any outgoing frames with the wireless interface MAC as the source MAC when the bridge send on a wireless interface ? Of course, this breaks the bridge transparency principle and might cause serious problem with BPDU, but on a simple (or simpler) configuration, without STP, this might work well for most level 3+ services. For example, an ARP answer can come for a different source MAC than the one stated in the ARP payload. So ARP should work well, even if the source MAC might look strange for someone having a close look at the frame. Also, the bridge global MAC (of br0) might be forced to the MAC of the wireless interface if there is only a single wireless interface in the bridge, probably causing BPDU to work well too. This is only theoretical and - I admit - a very dirty fix into the bridge code, but... better than noting. And by the way, may be this can be setup using ebtable, which is cleaner ! Any comments ? Nicolas.