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 auth
• courier-imap with ssl support
• amavis
• spamassasin
• clamav with automatic updates

Why I created this image: Simple mail server with Docker

informations:

• only config files, no *sql database required
• mails are stored in /var/mail/${domain}/${username}
• you should use a data volume container for /var/mail for data persistence
• email login are full email address (username1@my-domain.com)
• user accounts are managed in ./postfix/accounts.cf
• aliases and fowards/redirects are managed in ./postfix/virtual
• antispam rules are managed in ./spamassassin/rules.cf
• files must be mounted to /tmp in your container (see docker-compose.yml template)
• ssl is strongly recommended, you can provide a self-signed certificate, see below

installation

docker pull tvial/docker-mailserver

build

docker build -t tvial/docker-mailserver .

run

docker run --name mail -v "$(pwd)/postfix":/tmp/postfix -v "$(pwd)/spamassassin":/tmp/spamassassin -p "25:25" -p "143:143" -p "587:587" -p "993:993" -h mail.my-domain.com -t tvial/docker-mailserver

docker-compose template (recommended)

mail:
  # image: tvial/docker-mailserver
  build: .
  hostname: mail
  domainname: my-domain.com
  ports:
  - "25:25"
  - "143:143"
  - "587:587"
  - "993:993"
  volumes:
  - ./spamassassin:/tmp/spamassassin/
  - ./postfix:/tmp/postfix/

Volumes allow to:

• Insert custom antispam rules
• Manage mail users, passwords and aliases
• Manage SSL certificates

usage

docker-compose up -d mail

configure ssl

generate self-signed ssl certificate

You can easily generate a self-signed SSL certificate by using the following command:

docker run -ti --rm -v "$(pwd)"/postfix/ssl:/ssl -h mail.my-domain.com -t tvial/docker-mailserver generate-ssl-certificate

# Press enter
# Enter a password when needed
# Fill information like Country, Organisation name
# Fill "mail.my-domain.com" as FQDN
# Don't fill extras
# Enter same password when needed
# Sign the certificate? [y/n]:y
# 1 out of 1 certificate requests certified, commit? [y/n]y

# will generate:
# postfix/ssl/mail.my-domain.com-key.pem (used in postfix)
# postfix/ssl/mail.my-domain.com-req.pem (only used to generate other files)
# postfix/ssl/mail.my-domain.com-cert.pem (used in postfix)
# postfix/ssl/mail.my-domain.com-combined.pem (used in courier)
# postfix/ssl/demoCA/cacert.pem (certificate authority)

Note that the certificate will be generate for the container fqdn, that is passed as -h argument.

configure ssl certificate (convention over configuration)

If a matching certificate (files listed above) is found in postfix/ssl, it will be automatically setup in postfix and courier-imap-ssl. You just have to place them in postfix/ssl folder.

client configuration

# imap
username:  				<username1@my-domain.com>
password:  				<username1password>
server:    				<your-server-ip-or-hostname>
imap port: 				143 or 993 with ssl (recommended)
imap path prefix:		INBOX
auth method:			md5 challenge-response

# smtp
smtp port:				25 or 587 with ssl (recommended)
username:  				<username1@my-domain.com>
password:  				<username1password>
auth method:			md5 challenge-response

todo

Things to do or to improve are stored on Github, some open by myself. Feel free to improve this docker image.

wanna help?

Fork, improve and PR. ;-)