Linux Bridging of Tagged-VLAN (802.1q) Ethernet Traffic

[Lev Olshvang]

Hi,

just 2 cents:

The vconfig man says that many ethernet controllers will remove vlan 
tags in hardware, so I woulk check with a sniffer for a presence of the 
vlan tag in ethernet header first.
( And  see the vconfig set_flag  1 effect on a vlan interface. )



On 01/24/2011 11:31 PM, shimi wrote:
> On Mon, Jan 24, 2011 at 11:26 PM, Oron Peled<oron at actcom.co.il>  wrote:
>> On Monday, 24 בJanuary 2011 21:47:20 shimi wrote:
>>> I'm trying to run a Linux Bridge in order to manipulate traffic
>>> running between trunk ports on two switches.
>>>
>>> The ports on both ends pass all their traffic with VLAN tagging to
>>> both ends (i.e. both switches has the port set to 802.1q/trunk, and
>>> the traffic flow between the switches encapsulates many subnets on
>>> different VLANs)
>> Short googling turned out the following related links:
>>   - [LARTC] linux bridging vlans?
>>        http://mailman.ds9a.nl/pipermail/lartc/2006q1/018537.html
>>   - 802.1Q VLAN Tagging and Untagging on Linux?
>>        http://www.linuxsa.org.au/pipermail/linuxsa/2006-July/084589.html
>>
>> The point mentioned is that you should vconfig the *physical* interfaces
>> and then bridge the result. The reason given for this is that it is more
>> flexible (although more complex) -- e.g: you can bridge a physical
>> non-vlan capable interface to a specific vlan.
>>
>> I didn't test any of this personally...
>>
> Thanks, but, quoting my original message:
>
> I also tried intercepting VLAN traffic by creating VLANs on the
> physical interfaces with vconfig, then adding them to the br0 and also
> tried setting them up in promisc mode. This also didn't seem to have
> any effect.
>
> Any other idea?
>
> -- Shimi
>
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