XCmail is a MIME and multi POP3 capable mailtool for X11 using the Xclasses X11 layout library. Its main purpose is to read and write mail, allowing any kind of data to be attached. It can handle MIME types, has helpers to show different types, and can encode and decode binary data into ASCII to allow it to be transported as mail over the Internet. It has many built-in functions such as 2 vCards, unlimited POP3 servers, SMTP, SMTP after POP3, SMTP-AUTH (RFC2554), addressbook, encoders, filters, a special spam filter, spell checker, xface, and a new "virtual folder" concept. It also uses external programs to enhance its feature set. XCmail can be extended through a plugin interface.
XFMail is an X11 application for receiving electronic mail. It implements most of its email functionality internally so that it does not depend on a lot of extra packages. It supports POP3, MBOX, IMAP4, sendmail, and SMTP. It has built-in support for interfacing with PGP, GPG, ispell/aspell, faces, LDAP, and esound. It runs on most Unix variants.
xP provides an intuitive, high quality, graphical (X11) user interface to the University of Washington's PINE Messaging System. xP aims to provide an interface that is welcoming and easy to use for the new user, while still retaining the look, feel and key commands of PINE for the experienced user.
NullLogic Groupware is a modular Web-based groupware and email system designed for contact management and event scheduling. Additional features include private messaging, public discussion forums, webmail, shared bookmarks, file sharing, call tracking, order processing, an XML-RPC API, and integrated POP3 and SMTP servers.
ADJE WebMail is a set of Perl CGI scripts which provide a Web interface to existing email accounts on any POP3-compliant email server. The software provides a complete interface, including encoding/decoding attachments, email and URL markup in received emails, and an address book for each user.
The MIME Email message class composes and sends MIME encoded email messages. It features user-definable headers and body parts, support for plain text and HTML body, headers with non-ASCII text, HTML messages with embedded images, file attachments with content type detection, forwarding of messages as attachments, setting the error delivery address with the Return-Path header, and sub-classes for different delivery methods: mail, SMTP, Qmail, Sendmail, and Microsoft IIS or Exchange pickup folder. It also supports sending personalized bulk mail by replacing the message parts that differ for each recipient.