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.
Net_NNTP is a PHP/PEAR library for communication with NNTP servers. Net_NNTP handles connection and protocol-level commands (RFC977), including many non-standard commands (RFC2980), via a user-friendly API which hides the actual NNTP commands/syntax. Some knowledge about NNTP and general knowledge about email and MIME is required, since parsing of content and headers is left up to the user. Net_NNTP allows advanced users direct usage of NNTP commands via the separate protocol implementation. Net_NNTP includes a fully-functional NNTP to HTML gateway demo application.
Swift is a library for sending email messages from PHP Web sites and applications. It does not rely on PHP's native mail() function (which is known for using high server resources when sending multiple email messages). Instead, it communicates directly with an SMTP server or an MTA binary to send mail quickly and efficiently. It features custom headers, multiple encoding options, TLS support, embedded images, building and sending multipart messages, fast Cc and Bcc handling, batching messages with or without multiple "To"s, support for multiple attachments, setting message priorities, requesting read receipts, pluggable SMTP Authentication (LOGIN, PLAIN, MD5-CRAM, POP Before SMTP), anti-flooding support (reconnect every X email messages ), secure Socket Layer connections (SSL), and loadable plugin support with event handling features.
libspawner implements the MTA side of Sendmail's Milter (mail filter) protocol that is used by the MTA to delegate policy decisions to external daemons. The main purpose of this library is to enable other MTAs, or any mail-handling software, to talk to the existing mail filters that have been developed for Sendmail.
Open5066 is an implementation of the NATO NC3A STANAG 5066 protocol stack for HF radio communications. It aims to implement all of SIS (Annex A), DTS (Annex C), and some of the application layer (Annex F) functionality such as HMTP. The concrete embodiment of Open5066 is the s5066d daemon.
Jsmtpd is a small and modular SMTP server daemon. It is heavily based on plugins, and currently supports spam detection (Spamassassin, Jasen, RBL servers, and BlackList), anti-virus (Clam Antivirus), Recipient rewriting, and many other filters. Filtering is done with a customisable tree of filters. Almost all functionality is implemented as plugins, making it easy to fit your needs.