MySQLTuner is a script written in Perl that will assist you with your MySQL configuration and make recommendations for increased performance and stability.

a tool for backing up your data using rsync (if you want to get help, use https://lists.sourceforge.net/lists/listinfo/rsnapshot-discuss)

Contributed stuff for munin (plugins, tools, etc...)

Swaks - Swiss Army Knife for SMTP

NicTool: a DNS management solution

Finance::Quote module for Perl

qpsmtpd is a flexible smtpd daemon written in Perl

Interchange ecommerce framework

Mail::DMARC, a complete DMARC implementation in Perl

Turn a computer into a secure, full-featured, high-performance mail server

dspam-spamassassin Plugin

perl module for interfacing with vpopmail

Qmail::Deliverable