Install exim with Homebrew, apk, dnf, MacPorts, Nix, pacman, zypper

Project links

• Homepage
• Repository
• Upstream docs
• Package manager page

Commands and aliases

• exicyclog
• exigrep
• exim
• exim-4.99.3-2
• exim_checkaccess
• exim_ctl
• exim_dbmbuild
• exim_dumpdb
• exim_fixdb
• exim_id_update
• exim_lock
• exim_msgdate
• exim_tidydb
• eximstats
• exinext
• exipick
• exiqgrep
• exiqsumm
• exiwhat

Project history

The current Exim specification describes Exim as an MTA for Unix and Unix-like hosts, designed around permanently connected Internet systems but configurable for intermittent links. Its own introduction explicitly places it in the Smail 3 lineage: many ideas and user interfaces came from Smail, while the Exim codebase was new and later grew beyond that initial model.

Exim's documentation and distribution model are also part of its history. The project has long shipped a large reference specification, command-line man page, filter language documentation, upgrade notes, and per-release change logs. Source releases are published from exim.org, with signed tarballs and a separate public Git repository for people who want to track the source tree directly.

Adoption history

An Exim 3.20 overview from 2000 already described production use at sites handling hundreds of thousands of messages per day. The current documentation points to mailing lists for announcements, user support, development, and automated VCS messages, plus independent mirror sites, which reflects the classic Unix server-project adoption pattern: distro packages, local site policy, mailing-list support, and careful upgrades.

Exim gained popularity as a sendmail-compatible replacement without requiring administrators to learn sendmail configuration. Its current manual says Exim adopts the Sendmail command-line interface so it can replace /usr/lib/sendmail or /usr/sbin/sendmail for message submission, while still producing Exim-specific output for administrative commands such as queue listings.

How it is used

Exim is used to receive, queue, route, and deliver mail over SMTP and related transports. Administrators care about its runtime configuration file, router and transport model, ACLs, queue runner, logs, and privileged execution model because those determine how mail policy, local delivery, forwarding, relaying, and security boundaries behave on a server.

The package exposes a cluster of operational tools around the main exim binary, such as queue inspection, log grepping, database maintenance, and statistics commands. That shape is why it appears in package managers as a service-oriented package rather than a single-purpose CLI utility.

Why package nerds care

For package maintainers, Exim is a security-sensitive daemon with signed upstream releases, build-time paths, runtime privilege rules, and distro-specific defaults. The official manual notes that the runtime configuration filename is compiled in through CONFIGURE_FILE, which explains why packaged Exim builds often differ in configuration paths and default integration details.

Exim is also historically interesting because major policy behavior changed over time. The official DNSBL HOWTO notes that Exim 4.00 moved incoming-mail policy checks to ACLs, making Exim 4 configuration materially different from Exim 3 for common anti-abuse setups.

Timeline

• 2000: Exim 3.20 overview documented production use at high-volume sites.
• 4.00: Incoming mail policy checks moved to ACLs.
• 4.73: Runtime configuration file permission rules were tightened.
• 4.99.4: Current specification documents the modern Exim 4 series.

Related projects

• Smail 3 is the direct design predecessor named by Exim's own documentation.
• Sendmail is the compatibility target for Exim's message-submission command-line interface.
• DNSBL services, TLS libraries, DBM libraries, and content scanners are common integration points documented around Exim deployments.

Sources

• https://www.exim.org/
• https://www.exim.org/exim-html-current/doc/html/spec_html/ch-introduction.html
• https://www.exim.org/download.html
• https://www.exim.org/exim-html-current/doc/html/spec_html/ch-the_exim_runtime_configuration_file.html
• https://www.exim.org/howto/rbl.html
• https://www.exim.org/exim-html-3.20/doc/html/oview.html