Re: [Madwifi-users] Wireless bridge
Status: Beta
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From: Greg C. <ma...@at...> - 2004-08-10 21:24:07
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This is a concise and accurate explanation. We are starting to work on 4-address support in the driver. The question is about how to tie it to security and topology discovery. The current thinking is to rely on the 802.1 implementation in Linux for topology discovery. The easy way out for security would be WPA/PSK with some kind of hack to trigger the WPA protocol between APs. comments? Greg Michael Schwingen wrote: >On Tue, Aug 10, 2004 at 03:50:25PM +0200, Ulrik Mikaelsson wrote: > > >>My situation is the following: >> >> >>Computer A ---- Wire --- MadWifi 1(Master) ---- WLAN ---- MadWifi2(Managed) >>---- Wire ---- Computer B >> >>Both MadWifi 1 and 2 is configured to bridge their ath0 and eth0 interfaces. >> >>Most of this setup works, all the way to MadWifi2, but not as far as computer >>B. The thing is it seems like MadWifi 1 refuses to accept packets not tagged >>with MadWifi2:s MAC. I have been able to verify this by monitoring the >>network by a 3d computer directly attached to the network. >> >> > >This is the typical setup that requires WDS (wireless distribution system) >mode, which uses 4-address frames instead of the normal 3-address frames >that are used between an AP and a station. > >This is because the 802.11 protocol needs the MAC address of both WLAN >machines in the frame (to send RTS/CTS, ACK, ...), plus for bridging to >work transparently, you also need both the MAC addresses of the real packet >source and destination (Computer A and B) as in a normal ethernet packet. > >In a normal managed scenario, the managed host is either source or >destination, so the shorter 3-address frame is used. > > > >>Is this something that can be overridden, and if not, why not? Is it due to >>limitations in the MadWifi open-source driver, or is it in the HAL, the >>hardware, or even in the 802.11 standard forbidden to accept packet from >>non-directly connected MAC-addresses? >> >> > >The standard specifies the usage of WDS mode, because that is the only way >to get it working as a fully transparent bridge. There are solutions that >allow bridging behind a machine that is a WLAN client, but they require some >kind of NAT at the MAC address level and may not be fully transparent. > >I am not sure about the state of WDS support in Madwifi. > >cu >Michael > > >------------------------------------------------------- >SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media >100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33 >Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift. >http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285 >_______________________________________________ >Madwifi-users mailing list >Mad...@li... >https://lists.sourceforge.net/lists/listinfo/madwifi-users > > |