# Docker Mailserver [![ci::status]][ci::github] [![docker::pulls]][docker::hub] [ci::status]: https://img.shields.io/github/workflow/status/docker-mailserver/docker-mailserver/Build%2C%20Test%20%26%20Deploy?color=blue&label=CI&logo=github&logoColor=white&style=for-the-badge [ci::github]: https://github.com/docker-mailserver/docker-mailserver/actions [docker::pulls]: https://img.shields.io/docker/pulls/mailserver/docker-mailserver.svg?style=for-the-badge&logo=docker&logoColor=white [docker::hub]: https://hub.docker.com/r/mailserver/docker-mailserver/ A fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.). Only configuration files, no SQL database. Keep it simple and versioned. Easy to deploy and upgrade. [Why this image was created.](http://tvi.al/simple-mail-server-with-docker/) 1. [Included Services](#included-services) 2. [Issues and Contributing](./CONTRIBUTING.md) 3. [Requirements](#requirements) 4. [Usage](#usage) 5. [Examples](#examples) 6. [Environment Variables](./ENVIRONMENT.md) 7. [Release Notes](./CHANGELOG.md) ## Included Services - [Postfix](http://www.postfix.org) with SMTP or LDAP auth - [Dovecot](https://www.dovecot.org) for SASL, IMAP (or POP3), with LDAP Auth, Sieve and [quotas](https://github.com/docker-mailserver/docker-mailserver/wiki/Configure-Accounts#mailbox-quota) - [Amavis](https://www.amavis.org/) - [Spamassasin](http://spamassassin.apache.org/) supporting custom rules - [ClamAV](https://www.clamav.net/) with automatic updates - [OpenDKIM](http://www.opendkim.org) - [OpenDMARC](https://github.com/trusteddomainproject/OpenDMARC) - [Fail2ban](https://www.fail2ban.org/wiki/index.php/Main_Page) - [Fetchmail](http://www.fetchmail.info/fetchmail-man.html) - [Postscreen](http://www.postfix.org/POSTSCREEN_README.html) - [Postgrey](https://postgrey.schweikert.ch/) - [LetsEncrypt](https://letsencrypt.org/) and self-signed certificates - [Setup script](https://github.com/docker-mailserver/docker-mailserver/wiki/setup.sh) to easily configure and maintain your mailserver - Basic [Sieve support](https://github.com/docker-mailserver/docker-mailserver/wiki/Configure-Sieve-filters) using dovecot - SASLauthd with LDAP auth - Persistent data and state - [CI/CD](https://github.com/docker-mailserver/docker-mailserver/actions) - [Extension Delimiters](http://www.postfix.org/postconf.5.html#recipient_delimiter) (`you+extension@example.com` go to `you@example.com`) ## Requirements **Recommended**: - 1 Core - 1-2GB RAM - Swap enabled for the container **Minimum**: - 1 vCore - 512MB RAM **Note:** You'll need to deactivate some services like ClamAV to be able to run on a host with 512MB of RAM. Even with 1G RAM you may run into problems without swap, see [FAQ](https://github.com/docker-mailserver/docker-mailserver/wiki/FAQ-and-Tips). ## Usage ### Available image sources / tags The [CI/CD workflows](https://github.com/docker-mailserver/docker-mailserver/actions) automatically build, test and push new images to container registries. Currently, the following registries are supported: - [DockerHub](https://hub.docker.com/repository/docker/mailserver/docker-mailserver) - [GitHub Container Registry](https://github.com/orgs/docker-mailserver/packages?repo_name=docker-mailserver) All workflows are using the **tagging convention** listed below. It is subsequently applied to all images pushed to supported container registries: | Event | Ref | Commit SHA | Image Tags | |--------------|-----------------------|------------|-------------------------------| | `push` | `refs/heads/master` | `cf20257` | `edge` | | `push` | `refs/heads/stable` | `cf20257` | `stable` | | `push tag` | `refs/tags/1.2.3` | `ad132f5` | `1.2.3`, `1.2`, `1`, `latest` | | `push tag` | `refs/tags/v1.2.3` | `ad132f5` | `1.2.3`, `1.2`, `1`, `latest` | ### Get the tools Download the `docker-compose.yml`, `compose.env`, `mailserver.env` and the `setup.sh` files: ``` BASH wget https://raw.githubusercontent.com/docker-mailserver/docker-mailserver/master/setup.sh wget https://raw.githubusercontent.com/docker-mailserver/docker-mailserver/master/docker-compose.yml wget https://raw.githubusercontent.com/docker-mailserver/docker-mailserver/master/mailserver.env wget -O .env https://raw.githubusercontent.com/docker-mailserver/docker-mailserver/master/compose.env chmod a+x ./setup.sh # and make yourself familiar with the script ./setup.sh help ``` ### Create a docker-compose environment - [Install the latest docker-compose](https://docs.docker.com/compose/install/) - Edit the files `.env` and `mailserver.env` to your liking: - `.env` contains the configuration for Docker Compose - `mailserver.env` contains the configuration for the mailserver container - these files supports [only simple `VAR=VAL`](https://docs.docker.com/compose/env-file/) - don't quote your values - variable substitution is *not* supported (e.g. `OVERRIDE_HOSTNAME=$HOSTNAME.$DOMAINNAME`). - Variables in `.env` are expanded in the `docker-compose.yml` file **only** and **not** in the container. The file `mailserver.env` serves this case where environment variables are used in the container. - If you want to use a bare domain (host name = domain name), see [FAQ](https://github.com/docker-mailserver/docker-mailserver/wiki/FAQ-and-Tips#can-i-use-nakedbare-domains-no-host-name) ### Get up and running If you'd like to use SELinux, add `-Z` to the variable `SELINUX_LABEL` in `.env`. If you want the volume bind mount to be shared among other containers switch `-Z` to `-z` ``` BASH docker-compose up -d mail # without SELinux ./setup.sh email add [] ./setup.sh alias add postmaster@ ./setup.sh config dkim # with SELinux ./setup.sh -Z email add [] ./setup.sh -Z alias add postmaster@ ./setup.sh -Z config dkim ``` If you are using a LDAP setup the setup looks a bit different as you do not add user accounts directly. Postfix doesn't know your domain(s) and you need to provide it when configuring DKIM: ``` BASH ./setup.sh config dkim domain '[,]' ``` If you want to see detailed usage information, run `./setup.sh config dkim help`. ### Miscellaneous #### DNS - DKIM When keys are generated, you can configure your DNS server by just pasting the content of `config/opendkim/keys/domain.tld/mail.txt` to [set up DKIM](https://mxtoolbox.com/dmarc/dkim/setup/how-to-setup-dkim). #### Custom user changes & patches If you'd like to change, patch or alter files or behavior of `docker-mailserver`, you can use a script. Just place it the `config/` folder that is created on startup and call it `user-patches.sh`. The setup is done like this: ``` BASH # 1. Either create the config/ directory yourself # or let docker-mailserver create it on initial # startup /where/docker-mailserver/resides/ $ mkdir config && cd config # 2. Create the user-patches.sh script and make it # executable /where/docker-mailserver/resides/config/ $ touch user-patches.sh /where/docker-mailserver/resides/config/ $ chmod +x user-patches.sh # 3. Edit it /where/docker-mailserver/resides/config/ $ vi user-patches.sh /where/docker-mailserver/resides/config/ $ cat user-patches.sh #! /bin/bash # ! THIS IS AN EXAMPLE ! # If you modify any supervisord configuration, make sure # to run `supervisorctl update` and/or `supervisorctl reload` afterwards. # shellcheck source=/dev/null . /usr/local/bin/helper-functions.sh _notify 'Applying user-patches' if ! grep -q '192.168.0.1' /etc/hosts then echo -e '192.168.0.1 some.domain.com' >> /etc/hosts fi ``` And you're done. The user patches script runs right before starting daemons. That means, all the other configuration is in place, so the script can make final adjustments. #### Supported Operating Systems We are currently providing support for Linux. Windows is _not_ supported and is known to cause problems. Similarly, macOS is _not officially_ supported - but you may get it to work there. In the end, Linux should be your preferred operating system for this image, especially when using this mailserver in production. #### Support for Multiple Domains `docker-mailserver` supports multiple domains out of the box, so you can do this: ``` BASH ./setup.sh email add user1@docker.example.com ./setup.sh email add user1@mail.example.de ./setup.sh email add user1@server.example.org ``` #### Updating `docker-mailserver` ``` BASH docker-compose down docker pull docker.io/mailserver/docker-mailserver: docker-compose up -d mailserver ``` You're done! And don't forget to have a look at the remaining functions of the `setup.sh` script with `./setup.sh -h`. #### SPF/Forwarding Problems If you got any problems with SPF and/or forwarding mails, give [SRS](https://github.com/roehling/postsrsd/blob/master/README.md) a try. You enable SRS by setting `ENABLE_SRS=1`. See the variable description for further information. #### Exposed ports | Protocol | Opt-in Encryption ¹ | Enforced Encryption | Purpose | | :------: | :----------------------: | :-----------------: | :------------: | | SMTP | 25 | N/A | Transfer² | | ESMTP | 587 | 465³ | Submission | | POP3 | 110 | 995 | Retrieval | | IMAP4 | 143 | 993 | Retrieval | 1. A connection *may* be secured over TLS when both ends support `STARTTLS`. On ports 110, 143 and 587, `docker-mailserver` will reject a connection that cannot be secured. Port 25 is [required](https://serverfault.com/questions/623692/is-it-still-wrong-to-require-starttls-on-incoming-smtp-messages) to support insecure connections. 2. Receives email and filters for spam and viruses. For submitting outgoing mail you should prefer the submission ports(465, 587), which require authentication. Unless a relay host is configured, outgoing email will leave the server via port 25(thus outbound traffic must not be blocked by your provider or firewall). 3. A submission port since 2018, [RFC 8314](https://tools.ietf.org/html/rfc8314). Originally a secure variant of port 25. See the [wiki](https://github.com/docker-mailserver/docker-mailserver/wiki) for further details and best practice advice, especially regarding security concerns. ## Examples ### With Relevant Environmental Variables This example provides you only with a basic example of what a minimal setup could look like. We **strongly recommend** that you go through the configuration file yourself and adjust everything to your needs. The default [docker-compose.yml](./docker-compose.yml) can be used for the purpose out-of-the-box, see the [usage section](#usage). ``` YAML version: '3.8' services: mailserver: image: docker.io/mailserver/docker-mailserver:latest hostname: mail # ${HOSTNAME} domainname: domain.com # ${DOMAINNAME} container_name: mail # ${CONTAINER_NAME} ports: - "25:25" - "143:143" - "587:587" - "993:993" volumes: - maildata:/var/mail - mailstate:/var/mail-state - maillogs:/var/log/mail - ./config/:/tmp/docker-mailserver/ environment: - ENABLE_SPAMASSASSIN=1 - SPAMASSASSIN_SPAM_TO_INBOX=1 - ENABLE_CLAMAV=1 - ENABLE_FAIL2BAN=1 - ENABLE_POSTGREY=1 - ENABLE_SASLAUTHD=0 - ONE_DIR=1 - DMS_DEBUG=0 cap_add: - NET_ADMIN - SYS_PTRACE restart: always volumes: maildata: mailstate: maillogs: ``` #### LDAP setup ``` YAML version: '3.8' services: mailserver: image: docker.io/mailserver/docker-mailserver:latest hostname: mail # ${HOSTNAME} domainname: domain.com # ${DOMAINNAME} container_name: mail # ${CONTAINER_NAME} ports: - "25:25" - "143:143" - "587:587" - "993:993" volumes: - maildata:/var/mail - mailstate:/var/mail-state - maillogs:/var/log/mail - ./config/:/tmp/docker-mailserver/ environment: - ENABLE_SPAMASSASSIN=1 - SPAMASSASSIN_SPAM_TO_INBOX=1 - ENABLE_CLAMAV=1 - ENABLE_FAIL2BAN=1 - ENABLE_POSTGREY=1 - ONE_DIR=1 - DMS_DEBUG=0 - ENABLE_LDAP=1 - LDAP_SERVER_HOST=ldap # your ldap container/IP/ServerName - LDAP_SEARCH_BASE=ou=people,dc=localhost,dc=localdomain - LDAP_BIND_DN=cn=admin,dc=localhost,dc=localdomain - LDAP_BIND_PW=admin - LDAP_QUERY_FILTER_USER=(&(mail=%s)(mailEnabled=TRUE)) - LDAP_QUERY_FILTER_GROUP=(&(mailGroupMember=%s)(mailEnabled=TRUE)) - LDAP_QUERY_FILTER_ALIAS=(|(&(mailAlias=%s)(objectClass=PostfixBookMailForward))(&(mailAlias=%s)(objectClass=PostfixBookMailAccount)(mailEnabled=TRUE))) - LDAP_QUERY_FILTER_DOMAIN=(|(&(mail=*@%s)(objectClass=PostfixBookMailAccount)(mailEnabled=TRUE))(&(mailGroupMember=*@%s)(objectClass=PostfixBookMailAccount)(mailEnabled=TRUE))(&(mailalias=*@%s)(objectClass=PostfixBookMailForward))) - DOVECOT_PASS_FILTER=(&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n)) - DOVECOT_USER_FILTER=(&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n)) - ENABLE_SASLAUTHD=1 - SASLAUTHD_MECHANISMS=ldap - SASLAUTHD_LDAP_SERVER=ldap - SASLAUTHD_LDAP_BIND_DN=cn=admin,dc=localhost,dc=localdomain - SASLAUTHD_LDAP_PASSWORD=admin - SASLAUTHD_LDAP_SEARCH_BASE=ou=people,dc=localhost,dc=localdomain - SASLAUTHD_LDAP_FILTER=(&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%U)) - POSTMASTER_ADDRESS=postmaster@localhost.localdomain - POSTFIX_MESSAGE_SIZE_LIMIT=100000000 cap_add: - NET_ADMIN - SYS_PTRACE restart: always volumes: maildata: mailstate: maillogs: ```