Rspamd is an anti-spam system designed to work faster than SpamAssassin by using the event model and various optimizations. Its most important features include regexp and Lua rules for filtering different parts of messages, a number of built-in functions for analyzing messages, fuzzy hash support, SURBL filters, email and character table support, a control interface for remote managing and stats gathering, a Lua plugin system, statistics support (OSB/Bayes), and an AJAX-based Web interface.
SpamCheck is an email scanning and quarantine system for Linux systems. Making use of a number of open source technologies, including SpamAssassin, Exim, and MySQL, it provides an easy-to-use, but powerful method to filter email for your domain. Once configured, multiple domains can be added and administered with the Web interface. Email is scanned and scored, non-spam is then passed on to a destination email server, while spam is either blocked or quarantined. Individual users can log in and review their quarantined email, and manage their settings through the Web-based interface.
Synspam uses Netfilter NFQUEUE to catch the source IP address of any machine connecting to your mail server, running multiple tests against it (RBL check, regexp on the reverse name, etc.) before forwarding the connection to the MTA. In order to have as few false positives as possible, a scoring system is used. If the source IP address is believed to be a spammer IP address, the connection can be dropped. There is a dry run mode if you just want to test it, which is the default.
Baruwa (Swahili for letter or mail) is a Web 2.0 MailScanner front-end. It provides an easy to use interface for managing a MailScanner installation. It is used to perform operations such as releasing quarantined messages, spam learning, whitelisting and blacklisting addresses, monitoring the health of the services, etc. Baruwa is implemented using Web 2.0 features (AJAX) where deemed fit. Graphing is also implemented on the client side using SVG, Silverlight, or VML. It includes reporting functionality with an easy to use query builder. Results can be displayed as message lists or graphed as colorful and pretty interactive graphs. Custom MailScanner modules are provided to allow for logging of messages to the MySQL database with SQLite as backup and for managing whitelists and blacklists.
MailChariot's only mission is to get your incoming email (for example from /var/spool/mail), filter it through a spam filter, and put it into a spam or ham mailbox. If you don't agree with the spam filter's decision, you can move it to the notspam or notham mailbox and MailChariot will mark the message as ham or spam respectively. This design is mail client agnostic. It is ideal for use on shared hosts where the provided spam filtering is not effective enough.
Jaro Mail is an integrated suite of interoperable tools for GNU/Linux and Apple/OS X to manage email communication in a private way, without relying on online services (in fact, encouraging users to store email locally). It mainly features a system for mailinglist filtering, address-book integrated whitelisting, and long-term email storage and archiving with functions for fast search and usage statistics. It makes internal use of customized versions of popular Unix tools like Mutt, Fetchmail, Procmail, Mairix, and Msmtp.