Open Source C Mail Transfer Agents

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, calendaring, and mailing list services.

ESMTP MTA is a user configurable relay-only MTA with a sendmail-compatible syntax, based on libESMTP and supporting the AUTH (including the CRAM-MD5 and NTLM SASL mechanisms) and the StartTLS SMTP extensions.

Rumble is a mail server suite for SMTP (ESMTPSA), HTTP, POP3 and IMAP4v1 with an extensive C/C++ and Lua API for scripting. It comes with support for SSL/TLS, SQLite and MySQL and has a web-based administration and webmail feature. Additional included modules feature greylisting, DNS blacklisting, SpamAssassin support and dynamic performance scaling as well as a multithreaded structure that allows for clustering of multiple servers for one or all domains, and with the ease of the Lua API, you can create your own new server mailing lists, CRM software, e-marketing and other extensions within minutes.

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

A qmail patch which provides plug-in support for it`s SMTP daemon.

This is a milter which scans emails with CRM114

AISK is an acronym for Artificial Intelligence Spam Killer. It is a server side filter that acts as a kind of PROXY and uses SMTP to communicate with MTA. Main decision mechanism is based on artificial neural network capable of finding patterns, learning

ASMMS -- Anonymous SMTP Mail Message Sender ... is an simple mta, written in C, for sending mails through mail servers, which have no authentication (AUTH). It should work on nearly all POSIX systems, tested only with SunOS, Linux and HPUX.

SORBS - Spam and Open Relay Blocking System - NOT http://www.sorbs.net/ This project is to provide a SMTP proxy that automatically checks incoming SMTP connections for origination from a server with an unsecured SMTP server and/or Proxy server.

This project aims to be a personal data storage and administration system. It will be an advanced system for information and electronic mail management. The server will be accessible to any IMAPv4 compatible mail client.

The complete mail system consist of mail client written in php and mail transfer agent written in c language.

The EZ-qmail distribution is an EZ method for hobbyists / small businesses to try the qmail system for mail delivery. It provides an EZ to install, modern (patched) and working (integrated) qmail system onto which additional functionalities can be added

F1-Mailer : A simple Mailer in command line for windows users with MIME format. F1-Meiler allows people sending emails via SMTP relaying servers on the Web, with mail attachement. File attachment and email dating support. A tool to begin in Web/SMTP.

FLex Smtp Server is a Fast, Lightweight EXtendable Smtp Server. While having basic protocol support, is aimed to manage heavy traffic also in a burst modality.

FMTA is a simple SMTP/POP3 server designed to run on Fox boards (Fox board is a small but powerful embedded computer running a complete GNU/Linux system).

Forpost is an embeddable, interpreted stack-based(Forth-like) language which has simple, compact and effective implementation in ANSI C. Main features: heterogeneous arrays, higher-order functions, program/data equivalence.

Fork of the OpenBSD spamd for the FreeBSD operating system. See http://www.openbsd.org/spamd/ for the original spamd documentation. Please, report there only FreeBSD related bugs. If you want join to the project - write mail to the samm user.

An advanced qmail distribution based on qmail-sql which has SMTP, SMTPS, POP3, POP3S, IMAP, IMAPS services, a content scanner, spoofing protections, SMTP AUTH support, SMTP-after-POP/IMAP, PHP5 API, SPF support and much more...

IDMS DBMA is an effort to develop a highly scalable (c10k complient) plugin based mail agent aimed at fighting spam & viruses. Hopefully replacing hard-to-maintain, complex, resource hungry configurations used by small to large users today.

IVS Milter is a plugin based content filtering milter. It currently supports... Virus (ClamAV) & Spam (SpamAssassin) scanning, Content-type, Attachment type & Attachment filename matching

InfinyMail is an ODMR (RFC 2645) implementation, consisting of client and server. The client request its mail to the provider (ISP's MTA) via ODMR protocol.

KQ-Mail is a modular SMTP mail server using kernel queues to communicate between modules. In it\'s basic mode it is ideal to sit between the internet and your primary mail server to provide a buffer and or a SMTP RFC enforcement engine

LIBBY (Little Internet's Best Basic Yabber) is a simple SMTP server for home users or users of a small local network. Easy configuration and security are major features.

MSWeb is a client for Microsoft's Outlook Web Access (OWA). It is intended to deliver mail from a MS exchange server to a UNIX computer. For those who are opposed to 50 MB mailreaders.