diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -314,6 +314,7 @@ Comparison of NoSQL servers: http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-v
 *Security tools.*
 
 * [Fail2Ban](http://www.fail2ban.org/wiki/index.php/Main_Page) - Scans log files and takes action on IPs that show malicious behavior.
+* [SpamAssassin](https://spamassassin.apache.org/) - A powerful and popular email spam filter employing a variety of detection techniques.
 
 ## SMTP
 *SMTP servers.*