Problem: Bro listening on two ethernet interfaces

Ours works fine on linux with the interfaces set in etc/bro.cfg like:

BRO_CAPTURE_INTERFACE="eth2 eth3"

Tim Brooks

Vern Paxson wrote:

i looked at the c-code. i runned it on different machines and
on various interfaces. bro still drops most of the packets
when i force it to listen on two interfaces.

is it a libpcap problem?
a bro problem?
a linux problem?

I believe it's a Linux problem. We do this under FreeBSD in two different
ways, either merging the interfaces in the kernel into one logical interface
(via a custom patch), or at user level. While the in-kernel version
performs better, the user-level one isn't a disaster like you describe.

I also recall hearing others mention that multiple interfaces under Linux
do not work well in general. I don't use Linux, though, so can't comment
more directly.

Vern
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Tim Brooks
Security Engineer

National Center for Supercomputing Applications
605 East Springfield Avenue Champaign, IL 61820