Exim
Includes a current version download section, mailing lists, documentation and FAQs, website credits, and Y2K information.
http://www.exim.org

Advox Omnigate 6
Combines an e-mail gateway, sms and POP3 server. Includes news, datasheets and overview of products and services.
http://www.advox.se/

PostFix
Open source email server for Unix, IBM Public license.
http://www.postfix.org/

IA eMailServer
Supports mailing list, infoserver, robot and group mailbox features, and has spam control. Includes downloads, rewards, and requirements.
http://www.tnsoft.com/

VPOP3
An Internet e-mail server and gateway for small, and medium sized businesses. Has an overview, features, screenshots, prices, download and requirements. [Win95/98/Me/NT/2000]
http://www.pscs.co.uk/products/vpop3/

IMail Server
An SMTP/POP3/IMAP4/LDAP mail server with web interface for messaging and administration. Has anti-spam and anti-virus features. [Windows NT]
http://www.ipswitch.com/products/imail_server/

Sugarsoft Mail Server
A standard SMTP/POP3 server for Windows 95/98/NT with unlimited domains and mailboxes. Features dial-up, mail lists, auto reply, and anti spamming. Uses clean ASCII files.
http://www.sugarsoft.com/

netMailshar
Features SMTP/POP3 mail server with auto-dialer, advanced scheduler, autoresponder, message viewer, and email forwarding.
http://www.pppindia.com/intl/netmailshar/

Interchange Email Server
A server-based application integrating with any e-mail system, or a mixed environment containing multiple protocols. Includes information about different gateways, requests, and terms. [Win95/98/NT/2000]
http://www.ssimail.com/Interchange.htm

Mercury Mail Transport System
A free fully RFC-compliant server for Intel platforms. Includes POP3, SMTP, IMAP modules, advanced filtering, advanced mailing-list hosting. [Netware, Win95/98/NT/2000]
http://www.pmail.com/overviews/ovw_mercury.htm

WZI Consulting: Custom Mail Delivery Solutions
Includes chapters on how mail is delivered, fetchmail configuration, fixed IP solutions, sendmail ETRN command, batched SMTP solutions, setting up and testing UUCP.
http://www.wizzy.com/wizzy/mail.html

Teapop
Open source POP3 solution. Free download, documentation, FAQ. [Unix source/RPM]
http://www.toontown.org/teapop/

XMail
Includes free download, full documentation, mailing list, and forum. [Linux, Solaris, Windows NT]
http://www.xmailserver.org/

Alt-N Technologies
Developers of the MDaemon email server software, including Outlook connector, antivirus functionality and fax server. [Windows]
http://www.altn.com/

Nexorplore
A high capacity, multi-protocol message server management and security features.
http://www.nexor.com/messaging_products.asp

Kerio MailServer
A secure email server with webmail, anti-virus and anti-spam protection, allowing to collaborate via email, shared contacts, calendars and tasks.
http://www.kerio.com/kms_home.html

Mailgate Ltd
Features mail and proxy server, POP3 collection for SMTP only servers for small to medium sized businesses.
http://www.mailgate.com/

NT Mail Server Seattle Lab Software Review
A real user review of their mail server and list server software.
http://nt-mail-server.dallastexas.net/

eXtremail
Supports SMTP/POP3/IMAP4 mail protocols. Includes news, history, mailing lists, messageboard, downloads, and FAQ. [Linux]
http://www.extremail.com/

QwikMail SMTP
Designed to be a fast, secure, and efficient, simple to configure and maintain. Declares no internal mailer. [Linux]
http://qwikmail.sourceforge.net/smtpd/

MDaemon
Scalable Windows email server with built-in spam blocking, content and antivirus filtering. Includes full mailing list functions, remote administration and support for browser based mail clients.
http://www.ccsoftware.ca/mdaemon

PostMaster Email Server
Explains benefits, requirements, downloads for LAN users.
http://www.postmasteremailserver.com

Burrotech - Office Mail
Free POP and SMTP server including aliases, auto-dialling, and internal routing. [Win]
http://www.burrotech.com/officemail.php

MailEnable
Provides details of three different editions of scalable hosted messaging platform for Microsoft Windows.
http://www.mailenable.com/

INweb Mail Server
A POP3/SMTP mail server providing features for small and large businesses, and ISPs. Includes an installation and configuration guide, trial version download, and a list of features.
http://www.inwebmail.com/

popa3d
A tiny Unix POP3 server with security as its primary design goal.
http://www.openwall.com/popa3d/

IISPop
A POP3 only server, designed to be paired with the SMTP server bundled in Windows 2000/IIS 5. Has support, discussion, and download.
http://www.curtiscomp.com/iispop

SOHO Mail Server
A free small office/home office SMTP/POP3 mail server for Windows with dial-up support and flexible routing rules.
http://www.sohoserver.co.uk

DAWKCo Software
Includes POP3 Server and e-mail routing services, webmail extension for IIS SMTP server, and administration tools.
http://www.dawkco.com/software/

wodMailServer
A set of components to create standalone full mail server system on a network. Contains Pop3Server, ImapServer, SmtpServer and Mailbox components.
http://www.weonlydo.com/index.asp?showform=MailServer

CapeSoft Email Server
Features easy to use control over email domains, mailboxes and aliases for small or medium businesses and home environments. Has history and installation and configuration help. [Windows]
http://www.capesoft.com/utilities/emailserver/emailserver.htm

Mail Master
Designed for unlimited users with integrated anti-virus, user configurable spam-filter, web mail interface, disk quotas, POP3, IMAP, and multi-level management.
http://www.linuxmailmanager.com/

Isode M-Switch
A high performance SMTP message switch. Includes internet messaging, POP3, anti-virus and anti-spam solutions.
http://www.isode.com/products/m-switch-overview.html

The Newman Group
Offers integrated email messaging management solutions.
http://www.nofailemail.net/

Magic Mail Server
A complete installation of all features for Mail Server for the ISP and business market. Includes support for anti-spam techniques, virus scanning, management and user interfaces.
http://magicmail.linuxmagic.com/

Smail-3
Accepts mail messages from local files or remote hosts by SMTP or UUCP, and delivers them to remote hosts or to files or programs on the local machine. Includes features, release information, and support. [Unix]
http://www.weird.com/~woods/projects/smail.html

Courier mail server
An SMTP/IMAP/POP3 and webmail server with extensions for mailing list management and spam filtering. [GNU/Linux, Unix]
http://www.courier-mta.org

PostConf
A web-based, email server and gateway. Includes a documentation, support and demo.
http://www.postconf.com/

TekGuard
Free SMTP mail server and optional MS Outlook PlugIn with C# source code. Receive, filter, identify and eliminate incoming spam mail.
http://www.tekguard.com/

Intellipeer
Has built-in anti-spam technology, and supports groups and mailing lists. Includes installation procedure, customization, support, and downloads. [Win 2000/XP/2003]
http://www.intellipeer.com/

Ability Mail Server
Has help, configuration and tips section. Supports SMTP, POP3, IMAP4, and WebMail and features remote administration and virus protection. [Windows 98, Me, NT, 2000, XP and 2003]
http://www.code-crafters.com/abilitymailserver/

Postal Engine
Features e-mail products to enable organizations to use standards compliant components to reduce downtime, and increase performance.
http://www.postalengine.com/

Binc IMAP
GPL licensed IMAP4rev1 server for Maildir, written in C++. It strives to be stable, fast, flexible, and RFC compliant.
http://bincimap.org/

CMail
Enables to send and receive e-mails across the Internet and within LAN. Includes variability of features, screenshots, technical documents, OEM information, and awards. [Win 95/98/NT/Me/2000/XP]
http://www.computalynx.net/software/cmail/

CommuniGate Pro
Features multi-domain support, mailbox accounts with protection mechanisms enabling access to POP3/IMAP4 mail clients.
http://www.stalker.com/CommuniGatePro/

hMailServer
Has webmail, support for virtual domains, anti virus scanning, and distribution lists. Includes features, screenshots, download, forum and documents. [Windows NT/2000/XP]
http://www.hmailserver.com/

inFusion Mail Server
Uses ColdFusion, iHTML or Active State Perl to control mail delivery. [Win95/98/NT/2000]
http://www.coolfusion.com/products/ims/

IceWarp Mail Server
Integrates SSL secured email (SMTP/POP3/IMAP4) with antispam and antivirus, webmail access, instant messaging, voice, groupware, FTP and web server. For Windows and Linux.
http://www.icewarp.com/

SL Mail Pro
Web-based POP3 and SMTP email server software for Windows NT/2000 with 14-day free trial.
http://www.seattlelab.com/products/slmailpro/

iWayMail
Developed for schools and school districts. Has centralized maintenance, building level administration, spam filtering, and web mail access.
http://www.iwaymail.com/iwaymail_index.html

Mailtraq
An e-mail SMTP/POP3 and proxy server, with a mailing list server and intuitive WebMail service. Includes dialup manager, user accounting and content barring.
http://www.mailtraq.com/612/

Netscape Messaging Server
Shows its implementation, features, data sheet, FAQ, evaluation guide, and download.
http://wp.netscape.com/messaging/v3.5/

Openwave
Email server software for medium to large ISPs and telecommunication providers.
http://www.openwave.com/us/products/

Eudora Freeware
Includes Eudora Email, Internet Mail Server (EIMS) v1.x and a POP3 server for Unix (Qpopper).
http://eudora.qualcomm.com/free/

1st Class Mail Server 4.x
Commercial mailserver with unlimited domains, mailboxes and mailing lists, graphical administration tool.
http://www.1cis.com/download/1cismail.asp

WebEasyMail
Supportsa numerous standard protocols and services, has virus protection, and other securitz support. [NT/2000/XP]
http://www.winwebmail.net/

W2K Mail Server
Trial downloads, news, articles and reviews for Windows NT and 2000 products.
http://www.w2kmailserver.com/main/

SocketMail
Mail server on Windows with SMTP, POP3 and web messaging. 30 days trial download available.
http://www.socketmail.com/

Rockliffe
Offer secure SMTP, POP, IMAP, web, and wireless email software for service providers and businesses. [WinNT/2000]
http://www.rockliffe.com/

Atmail
A perl-based feature-rich web email system supporting access via web, WAP, POP3 or IMAP. Fully customizable, with web-admin, scheduler, migration scripts and Unix/Windows technical support.
http://atmail.com/

Dovecot
Secure IMAP and POP3 server. Download, mailing list archives, documentation, and details of bug reports.
http://www.dovecot.org/

Project Cyrus
An IMAP server developed at Carnegie Mellon University. (C, Perl) [GNU/Linux, Unix]
http://cyrusimap.web.cmu.edu//

AA Mail Server
Database-based server for Win2000/WinXP/Win2003 includes features of SMTP/POP3/SMTP Auth, ISP mailboxes binding, anti-spam, email monitoring, and UTF-8 web mail. Features, FAQ, Screenshot and Downloads. [Commercial, trial version]
http://www.aamailsoft.com/