Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.
The Perl ResourcePool provides a generic way to use connection caching for any kind of resources like Net::LDAP or DBI. It includes a LoadBalancer to spread load across different servers and increase overall performance and availibility of service. The ResourcePool and LoadBalancer are easily extendable to cover your needs.
ZoneMaster is a tool for zone file and name server management. It consists of a library that can configure BIND and a Web-based user interface that is used to access the data that is stored in a database. A bootstrap script allows you to initialize the database with all necessary information retrieved from an existing configuration. All modifications are saved as jobs in the database, and a job handler makes the necessary changes from time to time. The user interface is based on XSLT-stylesheets and can be easily modified.
Amethyst started as a port of Infobot to POE, continuing as a generic bot core with the ability to handle multiple connections using different protocols (not necessarily IRC) and soft route the incoming messages through a number of processing centres. One of these processing centres contains much of the original Infobot core.