The SeaMonkey project is a community effort to develop an all-in-one Internet application suite. It contains an Internet browser, email and newsgroup client with an included Web feed reader, HTML editor, IRC chat, and Web development tools, and is sure to appeal to advanced users, Web developers, and corporate users. It uses much of the Mozilla source code powering such successful siblings as Firefox, Thunderbird, Camino, Sunbird, and Miro.
phpGroupWare (formerly known as webdistro) is a multi-user groupware suite written in PHP. Its provides a Web-based calendar, todo-list, addressbook, email, news headlines, and a file manager. The calendar supports repeating events. The email system supports inline graphics and file attachments. The system as a whole supports user preferences, themes, user permissions, multi-language support, an advanced API, and user groups.
libSieve is an implementation of the Sieve mail sorting language originally developed for the Cyrus mail system. libSieve helps to bring mail sorting functionality into your mail server application without the need to reinvent the wheel. As a library, it is not intended for end users expecting a ready-to-run program.
libspopc is an easy-to-use POP3 client library written in C. It implements the client side of RFC 1939, providing an easy and quick way to support POP3 and POP3s (SSL) access in a program. It can download email headers and delete messages remotely without actualy downloading the message.
SPF is a new strategy for preventing junk mail. The present SMTP standard for email allows anyone to forge anyone else's email address. SPF verifies that the Sender address of an email message matches (according to some policy) the client IP address that submitted it. libspf2 is a complete and robust implementation of SPF which provides support for many MTAs. Support for new MTAs is in progress.
Dovecot is an IMAP server whose major goals are security and extreme reliability. It uses index files to optimally store the mailbox state, which makes it very fast even with huge mailboxes. Indexes won't prevent external mailbox updates, so Dovecot is still fully compatible with standard Maildir and mbox formats. There's also a fully featured POP3 server included.
LibESMTP is a library to manage posting (or submission of) electronic mail using SMTP to a preconfigured Mail Transport Agent (MTA) such as Exim. It may be used as part of a Mail User Agent (MUA) or another program that must be able to post electronic mail but where mail functionality is not the program's primary purpose. LibESMTP is not intended to be used as part of a program that implements a Mail Transport Agent.