Dear James,
>> It seems that when a 802.1q tagged packet is received in a physical
>> Linux interface (for example 'eth2') the behaviour is:
>>
>> 1. If there is some subinterface maching the tag, the packet is
>> deliver to that interface. For example, if the packet is tagged with
VLANID=200
>> and there is an eth2.200 interface, the packet is delivered to eth2.200
>> (and a 'tcpdump -i eth2.200', for example, would show it).
>>
>> 2. If there is no subinterface maching the tag, the packet is drop.
>> For example, if the packet is tagged with VLANID=300 and there is no
>> eth2.300, the packet is drop (and a 'tcpdump -i eth2' would never show
it).
>>
>> Is that right?
>>
>> In that case, I would like to know if is possible to change the
>> behaviour of item 2 (maybe with some configuration in the /proc/sys
hierarchy),
>> so a 'tcpdump -i eth2' shows the tagged packet.
>>
>> I'm asking this beacuse I would like to bridge a trunk of tagged
>> traffic (that comes at eth2 from/to a Cisco router) with a software
bridge in
>> the Linux box implemeted with brctl ('brctl addif somebridge eth2') , but
>> if the default behaviour is to drop tagged un-matched packets, this seems
>> imposible...
>
> What Ethernet adapter are you using (chipset or linux module name)?
The kernel module seems to be e1000
occ3-devb:~# dmesg | grep eth2
e1000: eth2: e1000_probe: Intel(R) PRO/1000 Network Connection
e1000: eth2: e1000_watchdog_task: NIC Link is Up 100 Mbps Full Duplex
My kernel version (in the case it would be needed) is 2.6.14.2.
> Do you have any ebtables rules in place (you will eventually need some
> to do what you want to do)?
I don't think so. In fact, it is the first time I heard about ebtables :)
Thank you for your interest!
Best regards,
--------------------
Fermin Galan Marquez
CTTC - Centre Tecnologic de Telecomunicacions de Catalunya
Parc Mediterrani de la Tecnologia, Av. del Canal Olimpic s/n, 08860
Castelldefels, Spain
Room 1.02
Tel : +34 93 645 29 12
Fax : +34 93 645 29 01
Email address: fermin.galan@xxxxxxx
