Does anyone have a recommendation for a decent (free) network monitoring program?  Preferably a linux distro.  I have tried a couple that I can't remember the names of right now but I'm just curious to see if there might be something better than what I've tried.

I am looking mostly for something that will detect issues, like botnet activity, etc.  Not interested in being a spy on the workers.

Ta!  

Didn't Wattsy recommend something a while back? Can't remember the name of it myself now... :C

It was a linux distro and I remember trying it out, but had to use the machine it was on for something else so didn't really get a chance to play.

He very well could have.  I can't remember anything anymore!  I downloaded nagios a bit ago.  As soon as I get these final updates installed I'm going to give it a try.

Sorry if I've already asked this!

Was it Backtrack?

I use that for exploit type stuff.  I want something that has monitoring agents n shit.

Doesn't ring a bell.

<searches frantically through the disks on my desk>

Backbox.

That's the one.

Have a look at this, it might be overkill but it is free.

http://www.alienvault.com/open-threat-exchange/projects#ossim-tab

i use the commercial version (Alienvault USM)

Most people seem to pay for their IPS. This list might have something.

Yeah, I'm just tired of fighting for every cent at this point.