ZMailer is an internet message transfer agent. It is intended for gateways or mail servers or other large site environments that have extreme demands on the abilities of the mailer. It was motivated by the problems of the Sendmail design in such situations. It is intended and designed as a multi-protocol mailer. The only protocol supported in this distribution is RFC822 (and variations).
hermes is a generic, transparent and multi-platform anti-spam SMTP proxy that uses a combination of techniques (like greylisting, throttling, DNS white/blacklisting, SPF, etc.) to stop spam from reaching your mailbox. Many mailboxes see a 98% spam reduction with no false positives, as hermes is not filtering email based on content, but on strict adherence to the SMTP standards. It's also compatible with most SMTP extensions like STARTTLS (for SSL security) and SMTP-AUTH (for user authentication).
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.
CommuniGate Pro is a high-end, industry strength Internet Mail server. It supports over 24 different operating systems including Linux/LinuxPPC,Solaris, MacOS X, FreeBSD, WindowsNT, BSDi, AIX, AS/400, HP/UX, Tru64, BeOS, IRIX, and S/390 for Linux. The CommuniGate Pro server takes full advantage of modern multi-threaded and multi-processor environments, and includes anti-spam protection, administration via the web, extensive multi-domain support, dial-up capabilities, cluster support, and unique IMAP multi-mailbox features. As a commercial product, it is distributed as keyware. The Free trial version is not time- or feature- limited.
Kerio MailServer is an email and collaboration suite that comes integrated with direct over-the-air (OTA) ActiveSync support, over 14 anti-spam layers (including SpamAssassin), dual anti-virus options (including a ClamAV plugin), collaboration features in Outlook, Entourage, Outlook Mobile, VersaMail, WebMail, and iCal, email archiving, and live automated backups. It supports a variety of SSL-encrypted communication protocols including POP3, IMAP, STMP, and HTTP for WebDAV, CalDAV, Web mail, and wireless ActiveSync. Wireless capabilities include direct email push, synchronization of calendar events, contacts, and tasks, and remote wipe for Windows Mobile devices to delete company data in the event the device is lost or stolen. Authentication options include Active Directory, Apple Open Directory, PAM, and an internal database. It can be administered remotely using an encrypted channel.
Buni Meldware Communication Suite is an enterprise groupware product providing an email server, calendar server, and a Web mail client. The Web mail portion is written using Adobe's Flash and provides a rich cross-browser experience. Protocol support includes IMAP, POP, SMTP, iCAL, WCAP, and more. It uniquely supports full database email storage as well as file system storage of emails on major database platforms, and is easily installed via a Web Start graphical installation process.
Net_NNTP is a PHP/PEAR library for communication with NNTP servers. Net_NNTP handles connection and protocol-level commands (RFC977), including many non-standard commands (RFC2980), via a user-friendly API which hides the actual NNTP commands/syntax. Some knowledge about NNTP and general knowledge about email and MIME is required, since parsing of content and headers is left up to the user. Net_NNTP allows advanced users direct usage of NNTP commands via the separate protocol implementation. Net_NNTP includes a fully-functional NNTP to HTML gateway demo application.