[Q-4.9-R]Questions About A Simple Bridge

[Jon Simola]

On 5/7/05, Jethro Wright III <jetman at mycbc.com> wrote:
> My problem is (per the diagram) rl0.
> dc0 and xl0 are anonymous interfaces (no IP addresses.)  rl0 has a local,
> private IP adress.  dc0 and rl0 are plugged into the same switch and therein
> lies the specific problem.

man bridge(4):

BUGS
     Care must be taken not to construct loops in the bridge topology.  The
     kernel supports only a primitive form of loop detection, by disabling
     some interfaces when a loop is detected.  No support for a daemon running
     the spanning tree algorithm is currently provided.

Plugging 2 interfaces into the same switch counts as a loop.

I've got similar problems here, caused by people using wireless shots
to connect random sites together and causing horrible problems in my
network:

May  5 09:25:23 cerebus /kernel: -- loop (10) 00.11.5c.d4.0c.00 to
fxp0 from em1 (active)
May  5 09:25:23 cerebus /kernel: -- loop (11) 00.11.5c.d4.0c.00 to em1
from fxp0 (active)
May  5 09:25:23 cerebus /kernel: -- loop (12) 00.11.5c.d4.0c.00 to
fxp0 from em1 (muted)
May  5 09:25:23 cerebus /kernel: -- loop (12) 00.11.5c.d4.0c.00 to em1
from fxp0 (muted)

That's the MAC of my upstream router, stopping my network dead. I have
to become very agressive with layer2 filtering with ipfw to keep the
bridge from seeing packets on the wrong interface.

-- 
Jon Simola
Systems Administrator
ABC Communications