Re: Bridging as sniffing method?

["Bojan Zdrnja" <bojan.zdrnja () gmail com>]

Hi Rob,

On 5/8/06, Rob Mason <rob () cissp org uk> wrote:
> Of these, I'm inclined to go with span ports or the network tap as the
> best solution.  However, bridging intrigues me.  Has anyone on the list
> had any experience (good or bad) with establishing a bridge to sniff
> switched LAN traffic?  I've tested out a working config using FreeBSD
> with two NICs and it appears to work OK, but I'm not confident of the
> robustness or integrity of the bridge - any advice would be most
> appreciated...

Span ports will be the easiest solution, provided that you have access
to the switch(es), of course. Keep in mind that if the network traffic
is very high that you will start loosing packets (as you will span all
other ports to this one).

I've been using OpenBSD firewalls in bridging mode for years and there
were absolutely no problems regarding robustness or integrity, and
those firewalls worked on some heavily utilized networks.

Cheers,

Bojan

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