docker-mailserver

A fullstack but simple mail server (smtp, imap, antispam, antivirus...). Only configuration files, no SQL database. Keep it simple and versioned. Easy to deploy and upgrade.

Includes:

postfix with smtp or ldap auth
dovecot for sasl, imap (and optional pop3) with ssl support, with ldap auth
saslauthd with ldap auth
amavis
spamassasin supporting custom rules
clamav with automatic updates
opendkim
opendmarc
fail2ban
fetchmail
postgrey
basic sieve support using dovecot
LetsEncrypt and self-signed certificates
persistent data and state (but think about backups!)
integration tests
automated builds on docker hub

Why I created this image: Simple mail server with Docker

Before you open an issue, please have a look this README, the Wiki and Postfix/Dovecot documentation.

Usage

Get latest image

docker pull tvial/docker-mailserver:latest

Create a `docker-compose.yml`

Adapt this file with your FQDN. Install docker-compose in the version 1.6 or higher.

Your configs must be mounted in /tmp/docker-mailserver/. To understand how things work on boot, please have a look to start-mailserver.sh

restart: always ensures that the mail server container (and ELK container when using the mail server together with ELK stack) is automatically restarted by Docker in cases like a Docker service or host restart or container exit.

version: '2'

services:
  mail:
    image: tvial/docker-mailserver:latest
    hostname: mail
    domainname: domain.com
    container_name: mail
    ports:
    - "25:25"
    - "143:143"
    - "587:587"
    - "993:993"
    volumes:
    - maildata:/var/mail
    - mailstate:/var/mail-state
    - ./config/:/tmp/docker-mailserver/
    environment:
    - ENABLE_SPAMASSASSIN=1
    - ENABLE_CLAMAV=1
    - ENABLE_FAIL2BAN=1
    - ENABLE_POSTGREY=1
    - ONE_DIR=1
    - DMS_DEBUG=0
    cap_add:
    - NET_ADMIN

volumes:
  maildata:
    driver: local
  mailstate:
    driver: local

for ldap setup:

version: '2'

services:
  mail:
    image: tvial/docker-mailserver:latest
    hostname: mail
    domainname: domain.com
    container_name: mail
    ports:
      - "25:25"
      - "143:143"
      - "587:587"
      - "993:993"
    volumes:
      - maildata:/var/mail
      - mailstate:/var/mail-state
      - ./config/:/tmp/docker-mailserver/
    environment:
      - ENABLE_SPAMASSASSIN=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)(mailEnabled=TRUE))"
      - 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
      - POSTMASTER_ADDRESS=postmaster@localhost.localdomain
    cap_add:
      - NET_ADMIN

volumes:
  maildata:
    driver: local
  mailstate:
    driver: local

Create your mail accounts

Don't forget to adapt MAIL_USER and MAIL_PASS to your needs

mkdir -p config
touch config/postfix-accounts.cf
docker run --rm \
  -e MAIL_USER=user1@domain.tld \
  -e MAIL_PASS=mypassword \
  -ti tvial/docker-mailserver:latest \
  /bin/sh -c 'echo "$MAIL_USER|$(doveadm pw -s SHA512-CRYPT -u $MAIL_USER -p $MAIL_PASS)"' >> config/postfix-accounts.cf

Generate DKIM keys

docker run --rm \
  -v "$(pwd)/config":/tmp/docker-mailserver \
  -ti tvial/docker-mailserver:latest generate-dkim-config

Now the keys are generated, you can configure your DNS server by just pasting the content of config/opendkim/keys/domain.tld/mail.txt in your domain.tld.hosts zone.

Note: you can also manage email accounts, DKIM keys and more with the setup.sh convenience script.

Start the container

docker-compose up -d mail

You're done!

Environment variables

Please check how the container starts to understand what's expected. Also if an option doesn't work as documented here, check if you are running the latest image!

Value in bold is the default value.

DMS_DEBUG

0 => Debug disabled
1 => Enables debug on startup

ENABLE_CLAMAV

0 => Clamav is disabled
1 => Clamav is enabled

ENABLE_SPAMASSASSIN

0 => Spamassassin is disabled
1 => Spamassassin is enabled

SA_TAG

2.0 => add spam info headers if at, or above that level

Note: this spamassassin setting needs ENABLE_SPAMASSASSIN=1

SA_TAG2

6.31 => add 'spam detected' headers at that level

Note: this spamassassin setting needs ENABLE_SPAMASSASSIN=1

SA_KILL

6.31 => triggers spam evasive actions

Note: this spamassassin setting needs ENABLE_SPAMASSASSIN=1

SA_SPAM_SUBJECT

***SPAM*** => add tag to subject if spam detected

Note: this spamassassin setting needs ENABLE_SPAMASSASSIN=1

ONE_DIR

0 => state in default directories
1 => consolidate all states into a single directory (/var/mail-state) to allow persistence using docker volumes

ENABLE_POP3

empty => POP3 service disabled
1 => Enables POP3 service

ENABLE_FAIL2BAN

0 => fail2ban service disabled
1 => Enables fail2ban service

If you enable Fail2Ban, don't forget to add the following lines to your docker-compose.yml:

cap_add:
  - NET_ADMIN

Otherwise, iptables won't be able to ban IPs.

ENABLE_MANAGESIEVE

empty => Managesieve service disabled
1 => Enables Managesieve on port 4190

ENABLE_FETCHMAIL

0 => fetchmail disabled
1 => fetchmail enabled

ENABLE_LDAP

empty => LDAP authentification is disabled
1 => LDAP authentification is enabled
NOTE:
- A second container for the ldap service is necessary (e.g. docker-openldap)
- For preparing the ldap server to use in combination with this continer this article may be helpful

LDAP_SERVER_HOST

empty => mail.domain.com
=> Specify the dns-name/ip-address where the ldap-server
NOTE: If you going to use the mailserver in combination with docker-compose you can set the service name here

LDAP_SEARCH_BASE

empty => ou=people,dc=domain,dc=com
=> e.g. LDAP_SEARCH_BASE=dc=mydomain,dc=local

LDAP_BIND_DN

empty => cn=admin,dc=domain,dc=com
=> take a look at examples of SASL_LDAP_BIND_DN

LDAP_BIND_PW

empty => admin
=> Specify the password to bind against ldap

LDAP_QUERY_FILTER_USER

e.g. "(&(mail=%s)(mailEnabled=TRUE))"
=> Specify how ldap should be asked for users

LDAP_QUERY_FILTER_GROUP

e.g. "(&(mailGroupMember=%s)(mailEnabled=TRUE))"
=> Specify how ldap should be asked for groups

LDAP_QUERY_FILTER_ALIAS

e.g. "(&(mailAlias=%s)(mailEnabled=TRUE))"
=> Specify how ldap should be asked for aliases

DOVECOT_USER_FILTER

e.g. "(&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n))"

DOVECOT_PASS_FILTER

e.g. "(&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n))"

OVERRIDE_HOSTNAME

empty => uses the hostname command to get the mail server's canonical hostname
=> Specify a fully-qualified domainname to serve mail for. This is used for many of the config features so if you can't set your hostname (e.g. you're in a container platform that doesn't let you) specify it in this environment variable.

POSTMASTER_ADDRESS

empty => postmaster@domain.com
=> Specify the postmaster address

ENABLE_POSTGREY

0 => postgrey is disabled
1 => postgrey is enabled

POSTGREY_DELAY

300 => greylist for N seconds

Note: This postgrey setting needs ENABLE_POSTGREY=1

POSTGREY_MAX_AGE

35 => delete entries older than N days since the last time that they have been seen

Note: This postgrey setting needs ENABLE_POSTGREY=1

POSTGREY_TEXT

Delayed by postgrey => response when a mail is greylisted

Note: This postgrey setting needs ENABLE_POSTGREY=1

ENABLE_SASLAUTHD

0 => saslauthd is disabled
1 => saslauthd is enabled

SASLAUTHD_MECHANISMS

empty => pam
ldap => authenticate against ldap server
shadow => authenticate against local user db
mysql => authenticate against mysql db
rimap => authenticate against imap server
NOTE: can be a list of mechanisms like pam ldap shadow

SASLAUTHD_MECH_OPTIONS

empty => None
e.g. with SASLAUTHD_MECHANISMS rimap you need to specify the ip-address/servername of the imap server ==> xxx.xxx.xxx.xxx

SASLAUTHD_LDAP_SERVER

empty => localhost

SASLAUTHD_LDAP_SSL

empty or 0 => ldap:// will be used
1 => ldaps:// will be used

SASLAUTHD_LDAP_BIND_DN

empty => anonymous bind
specify an object with priviliges to search the directory tree
e.g. active directory: SASLAUTHD_LDAP_BIND_DN=cn=Administrator,cn=Users,dc=mydomain,dc=net
e.g. openldap: SASLAUTHD_LDAP_BIND_DN=cn=admin,dc=mydomain,dc=net

SASLAUTHD_LDAP_PASSWORD

empty => anonymous bind

SASLAUTHD_LDAP_SEARCH_BASE

empty => Reverting to SASLAUTHD_MECHANISMS pam
specify the search base

SASLAUTHD_LDAP_FILTER

empty => default filter (&(uniqueIdentifier=%u)(mailEnabled=TRUE))
e.g. for active directory: (&(sAMAccountName=%U)(objectClass=person))
e.g. for openldap: (&(uid=%U)(objectClass=person))

SASL_PASSWD

empty => No sasl_passwd will be created
string => /etc/postfix/sasl_passwd will be created with the string as password

SMTP_ONLY

empty => all daemons start
1 => only launch postfix smtp

SSL_TYPE

empty => SSL disabled
letsencrypt => Enables Let's Encrypt certificates
custom => Enables custom certificates
manual => Let's you manually specify locations of your SSL certificates for non-standard cases
self-signed => Enables self-signed certificates

Please read the SSL page in the wiki for more information.

PERMIT_DOCKER

Set different options for mynetworks option (can be overwrite in postfix-main.cf)

empty => localhost only
host => Add docker host (ipv4 only)
network => Add all docker containers (ipv4 only)

VIRUSMAILS_DELETE_DELAY

Set how many days a virusmail will stay on the server before being deleted

empty => 7 days

ENABLE_POSTFIX_VIRTUAL_TRANSPORT

This Option is activating the Usage of POSTFIX_DAGENT to specify a ltmp client different from default dovecot socket.

empty => disabled
1 => enabled

POSTFIX_DAGENT

Enabled by ENABLE_POSTFIX_VIRTUAL_TRANSPORT. Specify the final delivery of postfix

empty: fail
lmtp:unix:private/dovecot-lmtp (use socket)
lmtps:inet:<host>:<port> (secure lmtp with starttls, take a look at https://sys4.de/en/blog/2014/11/17/sicheres-lmtp-mit-starttls-in-dovecot/)
lmtp:<kopano-host>:2003 (use kopano as mailstore)
etc.

squadramunter/docker-mailserver

docker-mailserver

Usage

Get latest image

Create a docker-compose.yml

Create your mail accounts

Generate DKIM keys

Start the container

Environment variables

DMS_DEBUG

ENABLE_CLAMAV

ENABLE_SPAMASSASSIN

SA_TAG

SA_TAG2

SA_KILL

SA_SPAM_SUBJECT

ONE_DIR

ENABLE_POP3

ENABLE_FAIL2BAN

ENABLE_MANAGESIEVE

ENABLE_FETCHMAIL

ENABLE_LDAP

LDAP_SERVER_HOST

LDAP_SEARCH_BASE

LDAP_BIND_DN

LDAP_BIND_PW

LDAP_QUERY_FILTER_USER

LDAP_QUERY_FILTER_GROUP

LDAP_QUERY_FILTER_ALIAS

DOVECOT_USER_FILTER

DOVECOT_PASS_FILTER

OVERRIDE_HOSTNAME

POSTMASTER_ADDRESS

ENABLE_POSTGREY

POSTGREY_DELAY

POSTGREY_MAX_AGE

POSTGREY_TEXT

ENABLE_SASLAUTHD

SASLAUTHD_MECHANISMS

SASLAUTHD_MECH_OPTIONS

SASLAUTHD_LDAP_SERVER

SASLAUTHD_LDAP_SSL

SASLAUTHD_LDAP_BIND_DN

SASLAUTHD_LDAP_PASSWORD

SASLAUTHD_LDAP_SEARCH_BASE

SASLAUTHD_LDAP_FILTER

SASL_PASSWD

SMTP_ONLY

SSL_TYPE

PERMIT_DOCKER

VIRUSMAILS_DELETE_DELAY

ENABLE_POSTFIX_VIRTUAL_TRANSPORT

POSTFIX_DAGENT

Create a `docker-compose.yml`