What is Snort?
Snort is a free and open source network intrusion prevention system (NIPS) and network intrusion detection system. Snort's open source network-based intrusion detection system (NIDS) has the ability to perform real-time traffic analysis and packet logging on IP networks. Snort performs protocol analysis, content searching, and content matching. The program can also be used to detect probes or attacks, including, but not limited to, operating system fingerprinting attempts, common gateway interface, buffer overflows, server message block probes, and stealth port scans.