smtp-cli is an SMTP command line client with support for advanced features such as STARTTLS, SMTP-AUTH, or IPv6. It also has scriptable message composition capabilities supporting anything from simple plain-text messages right up to building complex HTML emails with alternative plain-text part, attachments, and inline images. It's also a convenient tool for testing and debugging SMTP servers' setups. smtp-cli can be used to check a given server's capabilities, to test your server's setup, or to create and dispatch email messages. The command line interface is intuitive, and everything is scriptable and can run in a completely non-interactive mode from scripts or cron jobs. smtp-cli is ideal for shipping log files from remote machines, running periodic mail delivery test loops, etc.
exJello is a JavaMail provider that connects to a Microsoft Exchange server (actually, it uses the WebDAV interface exposed by Outlook Web Access). It is designed as a drop-in replacement for the standard POP3 and SMTP providers. This allows you to send and receive messages through your Exchange server in situations where a POP3/SMTP interface is not available (through a restrictive firewall, for example, or if your administrator simply does not provide a POP3 or SMTP gateway).
WAWAS is a full PHP application server. The main server core listens to any IP/port and passes data to any mounted protocol on the listener. Implemented protocols are HTTP1.1/1.0, Comet, Telnet, DNS, mail, and FTP. Each protocol runs modules that build response data based on the requests. Memory object persistence allows data and caches to be shared across protocols or time. All configuration uses XML. It can be launched as a daemon, with or without forked workers, and is nearly as fast as Apache in preliminary tests.
Built upon Maarch Framework, Maarch LetterBox is a complete mail management solution. It is developed exclusively by its user base. It handles incoming, outgoing, and internal mail. It ships with an inline editor to generate mail or answers from templates. It sends alerts and notifications on new mail, late mail, etc. It manages mail circulation between users through virtual mail baskets. It logs every action on documents and on the configuration of the application. It offers tools to monitor mail activity.
Scandalo is a very efficient and fast mail frontend for the clamdscan virus scanner. In other words, it is a simple mail filter that works as a wrapper for clamd, the famous Clamav antivirus daemon. Once integrated in maildrop or any MTA or MUA, it can quickly read messages and send them to the clamd process for virus scanning using the clamdscan utility. When a virus is found, the message is marked with a header, so you can easily set up your mail filter or MUA to drop, quarantine, or move the infected message to a mail folder.