Having an Intrusion Detection System isn’t optional for network admins that are audited. An IDS is also very handy to have as it shows you everything that is going on. You don't have to spend a lot of money on this, especially since most of the best tools are free. In my case, I wanted: network intrusion detection, network inventorying, and security scanning. I spent a lot of time messing around with separate packages for getting the functionality I wanted, but it was a pain to manage them all separately. I finally found an all-in-one system which met all of my requirements. OSSIM provides snort, nagios, ntop, and nessus (and various other security tools); this met all of my needs. It ... [More]