adding snort to security list

README.md

@@ -337,6 +337,7 @@ Comparison of NoSQL servers: http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-v
 
 * [Denyhosts](http://denyhosts.sourceforge.net/) - Thwart SSH dictionary based attacks and brute force attacks.
 * [Fail2Ban](http://www.fail2ban.org/wiki/index.php/Main_Page) - Scans log files and takes action on IPs that show malicious behavior.
+* [Snort](https://www.snort.org/) - Snort is a free and open source network intrusion prevention system (NIPS) and network intrusion detection system (NIDS) created by Martin Roesch in 1998.
 * [SpamAssassin](https://spamassassin.apache.org/) - A powerful and popular email spam filter employing a variety of detection techniques.
 
 ## Service Discovery