Exim

Spec sheet

What it does

Exim is a mail transfer agent for hosts running Unix or Unix-like operating systems.Read 8 Oct 2026 · exim.org

Download verification

Published source tarballs are cryptographically signed with OpenPGP, and signatures are distributed alongside them.Read 8 Oct 2026 · exim.org

Filtering

Users can use Sieve filters or Exim’s own filter language, which the manual describes as more powerful than Sieve.Read 8 Oct 2026 · exim.org

Intended use

The manual says Exim is designed for Internet mail transfer and that using it to send bulk unsolicited email conflicts with the project’s aims.Read 8 Oct 2026 · exim.org

Mail routing

Exim provides flexible facilities for routing mail and checking incoming mail.Read 8 Oct 2026 · exim.org

Mail transport

The implemented external transport mechanisms are SMTP and LMTP over TCP/IP, including IPv6.Read 8 Oct 2026 · exim.org

Platform support

The documentation lists configuration files for several operating systems, including Darwin (Mac OS X), FreeBSD, OpenBSD, Solaris, and GNU/Linux; it cautions that some older systems may no longer be testable.Read 8 Oct 2026 · exim.org

Policy controls

Access control lists can grant or deny access at points in the SMTP dialogue, including after recipient commands and at the end of a message.Read 8 Oct 2026 · exim.org

Release signing

The project says all releases receive a signed Git tag.Read 8 Oct 2026 · exim.org

Scanning integrations

When built with the content-scanning extension, Exim can pass messages to external virus or spam scanning software through its ACL mechanism.Read 8 Oct 2026 · exim.org

Security updates

The website identifies version 4.100.1 as a security release addressing four listed security issues.Read 8 Oct 2026 · exim.org

Support and community

The project provides announcement, development, and user mailing lists, including searchable archives for the user list.Read 8 Oct 2026 · exim.org

Virus and spam scanning limit

The manual says Exim’s basic incoming-message scanning is not comprehensive enough for full virus or spam scanning and recommends specialized additional software.Read 8 Oct 2026 · exim.org

Windows support

Configuration files exist for compiling Exim in the Cygwin environment on Windows, but the manual does not explain running Exim there.Read 8 Oct 2026 · exim.org

Plans and prices

Every Exim plan and price →

Where Specifiction places it

• Mail Server Software#9 of 348.1