Python SRS Library is a Python translation of the Perl reference implementation for SRS (Sender Rewriting Scheme) with easy to install packaging and built-in sendmail integration. SRS is needed when forwarding mail for SMTP authorization schemes that publish which IPs are authorized to send mail from a domain (for example SPF - Sender Policy Framework). It can also detect forged SMTP bounces by signing the return path for outgoing mail.
Forwards is a Horde module for setting user e-mail forwards via the .forward mechanism supported by several popular mailers. Forwards provides fairly complete support for setting .forward style forwards on Sendmail, Courier, or Qmail based systems via an FTP transport. It also has drivers for Mdaemon, Exim SQL, Exim LDAP, Custom SQL, and SOAP based systems.
Vacation is a Horde module for managing user email "vacation notices" or "auto-responders." It works via a local vacation program and the .forward style forwarding mechanism supported by several popular mailers. Currently, it provides fairly complete support for managing .forward style vacation notices on Sendmail or Courier mail based systems via an FTP transport. It also has some support for LDAP, Qmail, and Exim SQL based servers.
mysqmail is a replacement for the qmail standard checkpasswd that performs authentication with a MySQL table. After authentication, it sets up two environment variables that it uses to perform traffic accounting. For SMTP, it provides an alternative logger for the qmail-send program. Instead of logs, it writes the traffic to a MySQL table for the related domain.
Exim-Python is an extension to Exim that adds the ability to execute compiled Python functions and methods from within Exim configuration file string expansions. Since Exim uses string expansions heavily throughout it's operation, this feature allows powerful added control to an already very flexible mail server.
Spey is an SMTP proxy that sits between your existing mail server and the outside world, blocking spam using a greylisting technique. It is simple, lightweight, easy to install and configure, requires minimal changes to your existing mail server, is completely independent of which mail server you're using, and extremely effective. The author's spam intake has dropped from over a hundred messages a day to about 5. It uses the Sqlite database library as a backend.