Open Source Desktop Operating Systems Email Servers

Highly scalable/configurable Messaging Platform allowing users in a domain to be distributed on multiple hosts, has multiple queues. Provides virtual domains/users in MySQL. Modern MSP class qmail replacement with ESMTP, POP3/IMAP, QMTP, QMQP support

YPOPs! is an application which emulates a POP3/SMTP mail server and provides free POP3 and SMTP access to Yahoo! Mail. It does not depend on Yahoo's POP3/SMTP mail server. You can use a mail client of your choice!

Aegis Implicit Mail is a free and open source library which is designed to provide fast and developer friendly API to send emails using SMTP ports. Binaries are available in the form of NuGet package: https://www.nuget.org/packages/AIM Please check http://pki.tools/aim.html as well AIM Supports : * None Ssl Mails * Implicit Ssl Mails * Explicit Ssl Mails * Smtp Connection test * Detect Ssl type of mail server * Attachments for MIME and S/MIME message. * In-line attachment and separate file attachment * All content types and mimes * SMIME , Signed and Encrypted mails In an integrated way Sadly, Microsoft.Net.Mail Ssl Mails does not support Implicit Ssl Mail and it is still used by many servers, including port 465 of Gmail here AIM comes to make a readable and fast alternative to send your smtp mails. For unicode issues please refer to https://sourceforge.net/p/netimplicitssl/tickets/4/ . We really appriciate any help in testing of different encodings

Extensive High Availability Modules (XHAM) provides “active-active” failsafe solutions to your Linux Firewall, Gateway, Router, Email Server, NIDS (Snort), Proxy, Samba, MySQL (with NAS), and Apache.

A small, fast, secure, anti-spam SMTP mail server (MTA). Delivery to mbox files and Maildirs supported. qwik-smtpd supports RBL, relay checking, raw/custom message handlers, and more. Custom authentication via checkpassword and a qmail-compatible configu