pf and bridge question

[Marc Beyer]

Hi,

I have an OpenBSD 3.3 firewall which acts as a transparent bridge 
between our network (not NATted) and a router giving access to the rest 
of the world. The bridging interfaces are configured without IP address 
and a third (management) NIC is configured with an IP address inside our 
network's address space. A colleague of mine claims that this can lead 
to confusion in the routing/bridging code of the firewall and possible 
corruption of the arp table. He says that the management interface 
should never be in the same logical or physical network  as one of the 
two sides of the bridge, i.e. it should have an address in rfc1918 space 
and be physically connected to different networking hardware.

I have difficulty in understanding how this could be true and he cannot 
give me an explanation other than that he has had trouble with this in 
the past (running older versions of OpenBSD 3.2 with ipf). Can someone 
here enlighten me as to whether this is really a possible problem and if 
so how exactly some sort of corruption/glitch could happen?

Thanks a lot,

Marc

P.S. Naturally I am aware of the fact that having the management 
interface on a separate NATted network with it's own protection is a 
good thing security-wise, so that's not really my question.