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Re: Bridging and VLANs?

Tim Nelson <tnelson@rockbochs.com> wrote:

> The use case is that I need to bridge eth0 with eth0.2, allowing layer
> two traffic to pass seamlessly between interfaces, yet still leave
> eth0.3 in a usable state. The switch this system is connected to is
> for all intents and purposes outside of my control, which is the
> reason for the odd network setup. 

> What I'm finding by simply creating a new bridge br0 with members eth0
> and eth0.2 is no connectivity on eth0.2, and slow/quirky connectivity
> on eth0 (native connectivity to Debian 7.x host). In doing research,
> I've found suggestions of adding the VLAN interfaces to the bridge
> direct, resulting in a br0, br0.2, and br0.3, but the results were the
> same. Also, it has been suggested to use ebtables to filter the VLANs
> at layer 2, but I had no luck there either. 

The problem probably is that eth0 not only contains the untagged traffic
but also the tagged frames for VLAN 2. If you bridge eth0 and eth0.2 you
essentially loop the packages from and to VLAN2, because every package
"put into" eth0.2 will be seen on eth0 as well and thus bridged again
to eth0.2 etc.

I don't see any clean solution other than getting rid of the untagged
traffic on eth0 and only use tagged frames. Then you could bridge (for
example) eth0.10 and eth0.2 and everything should be fine.

But if you cannot change anything on the switch, you are out of luck.


Sigmentation fault. Core dumped.

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