[Bridge] Ethernet+Wireless Bridge?

Mark S. Mathews mark at linux-wlan.com
Mon Apr 28 07:04:53 PDT 2008


Heh.  I think the reason most folks think this should 'just work' is  
because: "hey, it's wireless ethernet, right?", wrong.  You can't  
ether-bridge natively across rs232, or bluetooth, or [any one of a  
hundred non-ethernet media]  either.

If your config consists of a STA and an AP, then the most forthright  
solution (not necessarily easy, mind you...takes a bit of tweaking to  
get it right) is to tunnel your ethernet frames across that link.   
I've used vtun for this purpose in the past.

And, as John pointed out, using routing, with or without NAT, is even easier.
Do you _really_ have to have a bridge?

Have fun,
-Mark


Quoting "John W. Linville" <linville at tuxdriver.com>:

> On Mon, Apr 28, 2008 at 11:25:07AM +0200, "Peter Valdemar Mørch  
> (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
> _______________________________________________
> Bridge mailing list
> Bridge at lists.linux-foundation.org
> https://lists.linux-foundation.org/mailman/listinfo/bridge
>



Mark S. Mathews

AbsoluteValue Systems      Web:    http://www.linux-wlan.com
721-D North Drive          e-mail: mark at linux-wlan.com
Melbourne, FL 32934        Phone:  321.259.0737
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