Roundup is a simple-to-use and install issue-tracking system with web, command-line xmlrpc, rest (in the 2.0 development line) and e-mail interfaces. It is based on the winning design from Ka-Ping Yee in the Software Carpentry Track design competition. Downloading the source allows you to start a demo instance in a few minutes to see if it will fill your needs.
Claws Mail is a GTK+ based, user-friendly, lightweight, and fast email client derived from Sylpheed. It can manage multiple mail accounts, displays messages in threads, categorized by filtering and colored, has a built-in adressbook. It supports SMTP, POP3, IMAP4, SSL and NNTP. It understands MBOX and MH storage. And it provides GnuPG encryption setup per default. Many extensions plugins (such as for spam filtering) are also available.
email2trac is a utility that converts email messages to Trac tickets. It features HTML message conversion, attachments, updating of tickets via email, command line options, a configuration file, Unicode support, spam detection, workflow support, and support for FullBlogPlugin and DiscussionPlugin.
Manitou-Mail is a 3-part database-driven email system: a PostgreSQL database for the storage engine, a Perl daemon that does send/receive and customizable analysis/indexing of the mail, and a mailer-like user interface (C++/Qt) connected to the database. The general goal is to provide a database-style architecture to handle email, not just for storage but at the application level too. Fast and shared access, fine-tuned security, robust storage, consistent backups, auditing, statistics, and custo
Mimeguard allows the configuration of policy regarding filetypes allowed in email. It can unpack multipart emails and examine MS Office files for macros, HTML, PDF and RTF files for illegal strings and 'look into' .zip files to see what filetypes are within them. It uses a system of allowed/not allowed filetypes that are defined in a config file. It's intended to be used within a script or system-ed from a parent process and returns and exit code that indicates if a file/mail is considered safe
"dl" is a simple file sharing service for quick/one-off file transfers. Upload a file to get a link you can share. Or create a sharing link to receive files from others. The uploaded files are automatically removed when left unused, requiring zero additional maintenance. "dl" is built for your users: easy to use with any browser, integrates smoothly with Thunderbird for large attachments, works on Android, Windows and OSX or straight from the command line for maximum convenience.
Postfix Admin is a PHP/web interface for managing mailboxes, virtual domains and aliases, fetchmail, and away or auto-reply messages. It requires MySQL/MariaDB or PostgreSQL, and optionally integrates with Squirrelmail / Roundcube.
Evolution is a personal information management application that provides integrated mail, calendaring and address book functionality.
Jaro Mail is an integrated suite of interoperable tools for GNU/Linux and Apple/OSX to manage e-mail communication in a private and efficient way, without relying too much on on-line services, in fact encouraging users to store e-mail locally. Rather than reinventing the wheel, Jaro Mail reuses some existing free and open source tools working since more than 10 years, generating their configurations and setting up integrations automatically.
cgipaf is a combination of three CGI programs. passwd.cgi allow users to update their password, viewmailcfg.cgi allows users to view their current mail configuration, and mailcfg.cgi updates the mail configuration with a .procmailrc in the user's home directory. All programs use PAM for user authentication. It is possible to run a script to update Samba passwords or NIS configuration when a password is changed. Users with too many invalid logins can be locked. A range of UIDs that are allowed to
GoldBug is a secure communication suite offering an E-Mail-Client, an Instant Chat Messenger, Filetransfer and a P2P Websearch within decentralized URL-Databases. Every of your transfers is multi-encrypted by default.
A utility to read the contents of the Postfix mail queue and filter according to arguments provided. Loosely based on the command exiqgrep which provides similar functionality for the exim mail server.
OpenDKIM is an open source implementation of the DKIM (RFC6376) email sender authentication system, derived from dkim-milter. It also supports ADSP/RFC5617, Vouch by reference/RFC5518, and experimentally ATPS/RFC6541. It works with any MTA supporting the sendmail milter API, such as Postfix. OpenDKIM provides a Lua-scriptable policy engine, LDAP and SQL database support, and statistic/reporting tools.