Mailcow is an open-source, Dockerized mail server suite that bundles Postfix, Dovecot, Rspamd, ClamAV, SOGo, ACME, Redis, MariaDB, Solr, Watchdog, and Nginx into a single, self-contained stack.
Why Mailcow exists:
- A modern alternative to monolithic builds (iRedMail, Mail-in-a-Box) and ancient hand-rolled Postfix/Dovecot setups.
- Each component runs in its own container, so upgrades are atomic and reproducible.
- Maintained by a small German team (Servercow / The Infrastructure Company GmbH) with an active community.
The container map:
| Container | Role |
|---|---|
| postfix-mailcow | SMTP MTA — accepts and relays mail on 25/465/587 |
| dovecot-mailcow | IMAP/POP3/Sieve/LMTP — mailbox storage and delivery |
| rspamd-mailcow | Content filtering, DKIM signing, greylisting |
| nginx-mailcow | TLS termination + reverse proxy for UI and webmail |
| sogo-mailcow | Groupware webmail + CalDAV/CardDAV/ActiveSync |
| mysql-mailcow | Account metadata, ACLs, transport maps |
| redis-mailcow | Caching for Rspamd, fail2ban, sessions |
| acme-mailcow | Let's Encrypt cert automation |
| watchdog-mailcow | Internal health probe + Telegram/email alerts |
| clamd-mailcow | Optional virus scanning |
Two flavors: Mailcow ships in a single docker-compose.yml and a config file (mailcow.conf) generated by ./generate_config.sh. There is no enterprise edition — everything is GPLv3.
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