tpop3d is yet another POP3 server. It is intended to be fast, extensible, and secure. It is especially extensible in regard to its authentication subsystem. Supported authentication mechanisms include auth-pam (Pluggable Authentication Modules) and auth-passwd to mediate access between users and their Unix-style mailboxes, auth-mysql which uses vmail-sql to mediate access to virtual-domain email, auth-ldap which allows authentication of users against an LDAP directory, auth-other which allows you to authenticate with an external program communicating via pipes, and auth-perl which allows you to authenticate users with custom Perl code. There is integrated support for POP-before-SMTP relaying. tpop3d supports traditional (BSD-format) mailspools and the maildir format of qmail.
TWIG is a Web-based groupware suite written in PHP, compatible with both PHP3 and PHP4. Its features include IMAP and POP3 email, Usenet newsgroups, contact management, scheduling, shared notes and bookmarks, a todo list, and meeting announcements. Any piece of information can be shared with others via group oriented access controls. By using only plain HTML, it is a simple, cross-platform, fast, and browser-independent way to access or share almost any kind of information, without the complexity or costs of other intranet/groupware packages. It is fully internationalized, with 24 translations.
vmail-sql is a complete virtual domains email setup, including sample Exim configuration sections, reference to tpop3d which will authenticate access to mailspools against the virtual user database, a set of admin-level scripts for administrating domains, and a Web-based control panel. Rather than storing the virtual domains setup in flat text files, it uses a MySQL database, allowing flexible administration strategies without concurrency hassles. It is designed for use in environments where several virtual domains are operated from a single machine/IP address.
vpopmail (vchkpw) is a collection of programs and a library to automate the creation and maintenance of virtual domain email configurations for qmail installations using either a single UID/GID or any valid UID/GID in /etc/passwd with a home directory. Features are provided in the library for other applications which need to maintain virtual domain email accounts. It supports named or IP-based domains. It works with vqadmin, qmailadmin, vqregister, sqwebmail, and courier-imap. It supports MySQL, Sybase, Oracle, LDAP, and file-based (DJB constant database) authentication. It supports SMTP authentication combined with the qmail-smtp-auth patch. It supports user quotas and roaming users (SMTP relay after POP authentication).
WMpop is a Window Maker dock app that monitors a local (mbox format) or POP3/APOP mailbox to inform you when mail arrives. It displays the amount of mail in the mailbox (or unread mail if checked in the preference screen), a scrolling text with the email address of the senders (only for local mailbox at the moment) and a status led, indicating mail checking progression and errors. It can be configured and personalized (icons and sound) via a GTK+ GUI.