mysqmail-qmail-pop3d is a replacement for the qmail standard checkpasswd that does authentication via a MySQL table. When done, it sets up two more environment variables, MYSQMAIL_USERNAME and MYSQMAIL_DOMAINNAME. The mysqmail qmail-pop3d replacement will use these variables to do the traffic accounting in the MySQL table for the account.
phPOP3clean is a spam, virus, and worm filtering system for POP3 email accounts. It is designed to run as a cron job and can catch spam based on links to blacklisted IPs, obfuscated words, or blacklisted phrases in the message body as well as attached-image spam, email worms, and corrupted or malformed emails.
stdnoj is a cross-platform C++ class library that includes classes for using portable strings, databases, SMTP, POP, NNTP, arrays, files, directories, logging, email, and sockets. While templates are used, no reliance upon STL or other (traditionally error-prone) technologies has been used, which increases portability between compilers.
aardmail is a package with useful tools for different kinds of mail handling. Current programs include a POP3 client (can be used to replace fetchmail for getting mail from POP 3 servers), an SMTP client, a minimalistic sendmail, and a minimalistic client for testing. All programs support SSL for encryption, verification, and authentication. IPv6 works.
AXIGEN is a fast, reliable and secure mail server with an open architecture. It is designed for easy management and allows full control of the email traffic from a central Web/CLI admin module. AXIGEN provides ESMTP, IMAP, and POP3 services and has been tested with standard mail clients. A special Webmail module enables email access and delivery from Web browsers. During the evaluation period, users are provided with full technical support.
Mail ConfiGuru is a standalone cross-platform tool and library that displays the configuration of email clients available to the currently logged-in user. It provides one interface to the settings of all supported email clients, which currently includes Mozilla Thunderbird, Mozilla Mail (SeaMonkey), MS Outlook, MS Outlook Express, KMail, and Ximian Evolution.
Twisted Mail provides client and server implementations of SMTP, POP3, and IMAP4. These differentiate themselves from the Python standard library implementations both by presenting a much higher-level, easy-to-use interface and in their server components, which allow the implementation of custom servers for each protocol without dealing with protocol-level issues. Twisted Mail includes a simple demonstration email server which accepts messages over SMTP, stores them in a Maildir arrangement, and can serve them to clients over POP3.
piAccess Mail is an agent that connects your phone's SMS messages to your email application's inbox. It talks to mobile phones over a serial connection (works with bluetooth, infrared, or cable links), while at the same time acting as a POP3 server to which any email client (Thunderbird, Evolution, Mail.app, Outlook, etc.) can connect to and retrieve messages from. All SMS messages in the phone's inbox are exposed as email messages.