Add Denyhosts in Security

README.md

@@ -313,6 +313,7 @@ Comparison of NoSQL servers: http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-v
 ## Security
 *Security tools.*
 
+* [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.
 
 ## SMTP