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Add Configuration

The Dovecot default configuration can easily be extended providing a config/ file. Dovecot documentation remains the best place to find configuration options.

Your docker-mailserver folder should look like this example:

├── config
│   ├──
│   ├──
│   └──
├── docker-compose.yml

One common option to change is the maximum number of connections per user:

mail_max_userip_connections = 100

Another important option is the default_process_limit (defaults to 100). If high-security mode is enabled you'll need to make sure this count is higher than the maximum number of users that can be logged in simultaneously.

This limit is quickly reached if users connect to the mail server with multiple end devices.

Override Configuration

For major configuration changes it’s best to override the dovecot configuration files. For each configuration file you want to override, add a list entry under the volumes key.

You will need to first obtain the configuration from the running container: mkdir -p ./config/dovecot && docker cp mailserver:/etc/dovecot/conf.d/10-master.conf ./config/dovecot/10-master.conf

      - maildata:/var/mail
      - ./config/dovecot/10-master.conf:/etc/dovecot/conf.d/10-master.conf


To debug your dovecot configuration you can use:

  • This command: ./ debug login doveconf | grep <some-keyword>
  • Or: docker exec -it mailserver doveconf | grep <some-keyword>

Note is included in the docker-mailserver repository. Make sure to grap the one matching your image version.

The config/ is copied internally to /etc/dovecot/local.conf. To check this file run:

docker exec -it mailserver cat /etc/dovecot/local.conf