AfterLogic XMail Server is an email server. It supports ESMTP, TLS/SSL secure connections, SMTP authentication, account and domain aliasing, anti-spam features (IP-based and email address based), mailing lists, logging, remote administration, the Finger protocol, filters, and custom mail processing. AfterLogic XMail Server is based on the XMail server, but features simultaneous multi-user access to a POP3 mailbox, the ability to configure port numbers via a configuration file, a Windows installer, and a Web administration tool with an AJAX interface.
BackupMX consists of two programs, 'Store' and 'Forward'. Store accepts SMTP connections, takes all mail given to it, and stores it in a file. Forward takes that file and forwards it over SMTP to a fixed destination. This is code for integrating into your own projects rather than using as is. It is suitable for creating a disaster-recovery mail handler, but would also make a good basis for a spam filter, a tarpit, a honeypot, or a greylist filter. It is written in simple C, and has no external dependencies such as libsmtp.
BarricadeMX provides very accurate, high performance spam and virus protection for Enterprise and ISP sites. Features include simple installation and administration, little if any end user interaction required, no quarrantine required, and an optional custom non-delivery receipt for all rejected messages. It uses a custom version of SpamAssassin along with many proprietary anti-spam techniques to achieve a guaranteed level of over 99% accurate spam detection with fewer than 0.1% false positives.
COMDOM Antispam is a high-capacity platform designed for the requirements of ISPs and other large organizations that must fight spam. COMDOM is a powerful anti-spam system operating as a stand alone mail gateway with relay control, authentication, and load balancing support. The system consequently can be used together with mail servers or as a stand alone gateway for several mail servers. The robustness, flexibility, and the high data throughput capacity of COMDOM Antispam allow for the software to be deployed for a range of solutions.
Citadel is an advanced messaging and collaboration system for groupware and BBS applications. Users can connect to Citadel using any telnet, WWW, or client software. Among the features supported are public and private message bases (rooms), electronic mail, real-time chat, paging, shared calendaring, address books, mailing lists, and more. Unlike other collaboration servers, Citadel provides its own data stores and is therefore extremely easy to install; you don't have to "bring your own" email and database because they're built in. The server is multithreaded and scalable. In addition, SMTP, IMAP, and POP3 servers are built-in for easy connection to Internet mail. Citadel is both robust and mature; it has been in production since 1987.
The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, Webmail, and mailing list services within a single consistent framework. Individual components can be enabled or disabled at will. Courier implements basic Web-based calendaring and scheduling services integrated in the Webmail module.
Deliver is a program for reliable and flexible local mail delivery. It's a perfect adjunct to your mail transport agent of choice (such as Sendmail or qmail). You can use it to kill spam, drop messages from specific senders, add a [LISTNAME] prefix to the subjects of messages that are delivered through mailing lists, and lots more.
EXACT is a program that implements POP-before-SMTP relay authentication. It supports UW-imap, Qpopper, Cyrus, Perdition, TeaPOP, EXIM, and Sendmail out of the box. POP-before-SMTP relay authentication is commonly used on systems that provide IMAP and/or POP services as well as SMTP services, to authenticate users for mail sending based on their previous authentication against an IMAP or POP server.