[LARTC] linux bridging problem: how to emulate 2 separate interfaces on a single one?

[Alexey Toptygin]

On Fri, 1 Jul 2005, Stephen Hemminger wrote:

>> LAN______________________________________________
>>                          |
>>                          | eth0 (no IP)
>>     _____________________|________________________
>>    |                     |          Linux Box (PC)|
>>    |             ________|________                |
>>    |            |                 |               |
>>    |            |       br0       |               |
>>    |            |     (no IP)     |               |
>>    |            |_________________|               |
>>    |           tap0  |        | tap1              |
>>    | 192.168.40.1/24 |        | 192.168.30.1/24   |
>>    |           MAC_0 |        | MAC_1             |
>>    |              ___|________|____               |
>>    |             |                 |              |
>>    |             | OS TCP-IP stack |              |
>>    |             |                 |              |
>>    |             |_________________|              |
>>    |                 | | | |                      |
>>    |                 | | | |                      |
>>    |                Processes                     |
>>    |                                              |
>>    |                                              |
>>    |______________________________________________|

[snip]

> It should work if the tap interface looks sufficiently like Ethernet.
> You probably need filter rules to make sure and drop packets intended for
> the other network get dropped and to prevent broadcast leakage.

The way I interpret the drawing, ISTM that Antonio has the bridge a layer 
below the tap devices (even though it's drawn a layer above). I don't 
think that's a very sane idea...

The crux of the problem seems to be that Antonio wants a single physical 
ethernet card to use two different MAC adresses, which I don't think 
briding is ever going to solve. This is, perhaps, possible by putting the 
card into promiscuous mode, and using some clever ebtables mangling.

 			Alexey