AMaViS: www.amavis.org
Cyrus IMAP Server and Cyrus SASL: asg.web.cmu.edu/cyrus
Linux HA Heartbeat: www.linux-ha.org/heartbeat
IMAP Proxy: www.imapproxy.org
OpenLDAP: www.openldap.org
Postfix: www.postfix.org
Postal: www.coker.com.au/postal
SecuritySage: www.securitysage.com
Silicon Graphics, Inc. XFS: oss.sgi.com/projects/xfs
Spamhaus XBL: www.spamhaus.org/xbl
Spamity: www.collaboration-world.com/spamity
SquirrelMail: www.squirrelmail.org