Courier Mail Server
The facts below are what the maker publishes about Courier Mail Server, checked and dated. Our editors have not written about it yet.
Plans and prices
From Courier Mail Server's own pricing page, checked 5 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Courier Mail Server | Free | Source code distributed under the GNU General Public License |
The facts
Each one read from Courier Mail Server's own pages, with the date it was checked.
What it does
- Authentication
- Authentication options include PAM, LDAP, MySQL, and PostgreSQL, with PostgreSQL identified as beta on the features page.checked 5 Oct 2026
- Calendaring
- Its webmail module includes basic web-based calendaring and scheduling, including a personal event calendar.checked 5 Oct 2026
- Compatibility
- Courier can be installed on systems previously running sendmail or Qmail, but the site says it is not a fully compatible replacement for either.checked 5 Oct 2026
- Deployment
- It can act as an intermediate mail relay, receive mail for multiple domains, or do both.checked 5 Oct 2026
- Distribution
- The download page offers the complete server source tarball and separate packages for components including IMAP, SqWebMail, and maildrop.checked 5 Oct 2026
- Download
- The download page lists Courier 2.0.7, dated 02-Aug-2026, as a source code tarball containing the mail server, IMAP server, webmail server, and maildrop filter.checked 4 Oct 2026
- Filtering
- Integrated mail filtering supports administrator-installed external filters and recipient-specified rules through maildrop.checked 5 Oct 2026
- Integrations
- The server can use LDAP, MySQL, or PostgreSQL-based authentication databases and supports LDAP-based mail routing.checked 5 Oct 2026
- Limitations
- Courier does not implement ETRN and is not a fully compatible replacement for sendmail or Qmail; its integrated mailbox servers do not support mbox.checked 4 Oct 2026
- Limits
- Courier does not implement ETRN, and its integrated mailbox access components do not support mbox mailboxes.checked 5 Oct 2026
- Mailing lists
- Courier includes a mailing list manager with automatic bounce processing.checked 4 Oct 2026
- Mail services
- Courier is an integrated mail and groupware server providing ESMTP, IMAP, POP3, webmail, and mailing list services.checked 5 Oct 2026
- Mail storage
- Maildir is its native mail storage format, and integrated IMAP, POP3, and webmail components support maildir-based mailboxes only.checked 5 Oct 2026
- Product
- Courier is an integrated mail and groupware server providing ESMTP, IMAP, POP3, webmail, and mailing list services.checked 4 Oct 2026
- Relay protection
- The site says Courier is a closed mail relay by default and cannot accidentally be configured as a completely open relay.checked 5 Oct 2026
- Security
- Courier supports STARTTLS and SSL for ESMTP, IMAP, POP3, and webmail; its ESMTP client can require a certificate signed by a trusted root CA.checked 5 Oct 2026
- Standalone components
- The IMAP server, SqWebMail webmail CGI, and maildrop filter are also offered as separate packages usable with other mail servers.checked 4 Oct 2026
- Storage
- Maildir is its native storage format; the integrated POP3, IMAP, and webmail servers work with maildir mailboxes only.checked 4 Oct 2026
- Support
- The site lists an unmoderated courier-users mailing list for questions, bug reports, and comments, plus a separate read-only announcement list.checked 4 Oct 2026
- Transport security
- The site lists STARTTLS and SSL support for ESMTP, IMAP, POP3, and webmail, and says the ESMTP client can require trusted-root-signed X.509 certificates.checked 4 Oct 2026
- Web administration
- Most configuration can be adjusted through a web-based administration module.checked 5 Oct 2026
Where it runs
- Platforms
- The source should compile on most Linux and BSD-based POSIX operating systems, and may compile on Solaris and AIX with additional tools.checked 5 Oct 2026
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