Clam AntiVirus is an anti-virus toolkit designed especially for email scanning on mail gateways. It provides a number of utilities, including a flexible and scalable multi-threaded daemon, a commandline scanner, and a tool for automatic database updates. The core of the package is an anti-virus engine available as a shared library.
Thunderbird is a total redesign of the Mozilla mail component to produce a cross-platform, stand-alone mail application using the XUL user interface language. It has many new features, among them the ability to customize your toolbars the way you want them. a new look and feel with a large number of downloadable themes which alter the appearance of the client, and the ability to add UI extensions.
Fetchmail is a free, full-featured, robust, well-documented remote-mail retrieval and forwarding utility intended to be used over on-demand TCP/IP links (such as SLIP or PPP connections). It supports every remote-mail protocol now in use on the Internet: POP2, POP3, RPOP, APOP, KPOP, all flavors of IMAP, and ESMTP ETRN, ODMR, SMTP, LMTP, and local delivery agents.
Cerb is a fast and flexible Web-based platform for business collaboration and automation. It helps you remember anything about anyone, collaborate from anywhere, deftly reply to a flood of email, automate, stay informed, capture feedback, track time, flag opportunities, manage tasks, share expert knowledge, and otherwise execute efficiently.
imapsync is a tool for facilitating incremental recursive IMAP transfers from one mailbox to another. It is useful for mailbox migration or backup, and reduces the amount of data transferred by only copying messages that are not present on both servers. Read, unread, and deleted flags are preserved, and the process can be stopped and resumed. The original messages can optionally be deleted after a successful transfer.
The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, Webmail, and mailing list services within a single consistent framework. Individual components can be enabled or disabled at will. Courier implements basic Web-based calendaring and scheduling services integrated in the Webmail module.
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.