Simple and full-featured mail server as a set of multiple docker images includes :
- Postfix : a full set smtp email server supporting custom rules
- Dovecot : secure imap and pop3 email server
- Amavis : content filter implementing decoding, processing and checking e-mails
- Spamassassin : anti-spam filter
- Clamav : antivirus with automatic updates
- OpenDKIM : implementation of DKIM (Domain Keys Identified Mail)
- OpenDMARC : implementation of DMARC (Domain-based Message Authentication, Reporting & Conformance)
- Sieve : email filtering (vacation auto-responder, auto-forward...etc)
- Fetchmail : fetch e-mails from external IMAP/POP3 server into local mailbox
- Postgrey : greylisting policy server
- Gross : greylisting of suspicious sources
- Rainloop : web based email client
- Postfixadmin : web based administration interface
- NSD : authoritative DNS server with DNSSEC support
- Nginx : web server with HTTP/2 and TLS 1.3 (DRAFT), statically linked against BoringSSL
- SSL : lets encrypt and self-signed certificates support
- Supporting multiple virtual domains over MySQL backend
- Integration tests with Travis CI
- Automated builds on DockerHub
# Pull from hub.docker.com :
docker pull hardware/mailserver
# or build it manually :
docker build -t hardware/mailserver https://github.com/hardware/mailserver.git#master
Note : Change your hostname / domain name, and adapt to your needs
See Reverse proxy configuration
Start the mailstack :
docker-compose up -d
See Postfixadmin initial configuration
See Rainloop initial configuration
HOSTNAME CLASS RECORD TYPE VALUE
------------------------------------------------------------------------------------------------
mail IN A SERVER_IPV4
@ IN MX 10 mail.domain.tld.
@ IN TXT "v=spf1 a mx ip4:SERVER_IPV4 ~all"
mail._domainkey IN TXT "v=DKIM1; k=rsa; p=DKIM Public Key"
_dmarc IN TXT "v=DMARC1; p=reject; rua=mailto:postmaster@domain.tld; ruf=mailto:admin@domain.tld; fo=0; adkim=s; aspf=s; pct=100; rf=afrf; sp=reject"
The DKIM public key is available on host here :
/mnt/docker/mail/opendkim/domain.tld/mail.txt
See NSD initial configuration, if you want to setup your own authoritative dns server with dnssec support 🔒
You can audit your mailserver with the following assessment services :
At first launch, the container takes few minutes to generate SSL certificates (if needed), Diffie-Hellman parameters, DKIM keypair and update clamav database, all of this takes some time, be patient...
You can check startup logs with this command :
docker logs -f mailserver
| Variable | Description | Type | Default value |
|---|---|---|---|
| VMAILUID | vmail user id | optional | 1024 |
| VMAILGID | vmail group id | optional | 1024 |
| VMAIL_SUBDIR | Individual mailbox' subdirectory | optional | |
| OPENDKIM_KEY_LENGTH | Size of your DKIM RSA key pair | optional | 2048 |
| DBHOST | MariaDB instance ip/hostname | optional | mariadb |
| DBPORT | MariaDB instance port | optional | 3306 |
| DBUSER | MariaDB database username | optional | postfix |
| DBNAME | MariaDB database name | optional | postfix |
| DBPASS | MariaDB database password | required | null |
| ADD_DOMAINS | Add additional domains to the mailserver separated by commas (needed for dkim keys etc.) | optional | null |
| DISABLE_CLAMAV | Disable virus scanning | optional | false |
| DISABLE_SPAMASSASSIN | Disable SPAM checking | optional | false |
| DISABLE_SIEVE | Disable ManageSieve protocol | optional | false |
| GREYLISTING | Enable greylisting policy server | optional | off |
| ENABLE_POP3 | Enable POP3 protocol | optional | false |
| ENABLE_FETCHMAIL | Enable fetchmail forwarding | optional | false |
| FETCHMAIL_INTERVAL | Fetchmail polling interval | optional | 10 |
| RECIPIENT_DELIMITER | RFC 5233 subaddress extension separator (single character only) | optional | + |
If DISABLE_CLAMAV and DISABLE_SPAMASSASSIN are both set to true, Amavis is also completely disabled.
The supported values for GREYLISTING are off, gross or postgrey. Gross is a more advanced greylisting server which blocks only hosts with a bad DNSBL reputation.
Currently, only a single RECIPIENT_DELIMITER is supported. Support for multiple delimiters will arrive with Dovecot v2.3.
FETCHMAIL_INTERVAL must be a number between 1 and 59 minutes.
/mnt/docker
└──mail
├──postfix
│ custom.conf
├──postgrey
│ postgrey.db
│ ...
├──gross
│ grossd.state
├──sieve
│ default.sieve
│ default.svbin
├──opendkim
│ ├──domain.tld
│ │ mail.private
│ │ mail.txt
├──ssl
│ ├──dhparams
│ │ dh512.pem
│ │ dh2048.pem
│ ├──live (Let's Encrypt or other CA)
│ │ ├──mail.domain.tld
│ │ │ privkey.pem
│ │ │ cert.pem
│ │ │ chain.pem
│ │ │ fullchain.pem
│ ├──selfsigned (Auto-generated if no certificate found)
│ │ cert.pem
│ │ privkey.pem
├──vhosts
│ ├──domain.tld
│ │ ├──user
│ │ │ .dovecot.sieve -> sieve/rainloop.user.sieve
│ │ │ .dovecot.svbin
│ │ │ ├──mail
│ │ │ │ ├──.Archive
│ │ │ │ ├──.Drafts
│ │ │ │ ├──.Sent
│ │ │ │ ├──.Spam
│ │ │ │ ├──.Trash
│ │ │ │ ├──cur
│ │ │ │ ├──new
│ │ │ │ ...
│ │ │ ├──sieve
│ │ │ │ rainloop.user.sieve (if using rainloop webmail)
To use Let's Encrypt certificates, setup your docker-compose.yml file like this :
mailserver:
image: hardware/mailserver
volumes:
- /mnt/docker/nginx/certs:/etc/letsencrypt
...
nginx:
image: wonderfall/boring-nginx
volumes:
- /mnt/docker/nginx/certs:/certs
...
Then generate Let's Encrypt certificates with xataz/letsencrypt, you can use other tools like lego if you want.
docker-compose stop nginx
docker run -it --rm \
-v /mnt/docker/nginx/certs:/etc/letsencrypt \
-p 80:80 -p 443:443 \
xataz/letsencrypt \
certonly --standalone \
--rsa-key-size 4096 \
--agree-tos \
-m contact@domain.tld \
-d mail.domain.tld \ # <--- Mail FQDN is the first domain name, very important !
-d webmail.domain.tld \
-d postfixadmin.domain.tld
docker-compose up -d
-
⚠️ The common name of your ssl certifcate MUST be the same as your server's FQDN (for example, let's encrypt live subfolder name must be equal to domainname & hostname values of docker-compose file). Don't forget to add your FQDN in command above in first position. -
If you do not use let's encrypt, a default self-signed certificate (RSA 4096 bits SHA2) is generated here :
/mnt/docker/mail/ssl/selfsigned/{cert.pem, privkey.pem}.
Put your certificates in /mnt/docker/nginx/certs/live/mail.domain.tld
- privkey.pem : Private key for the certificate
- cert.pem : Server certificate only
- chain.pem : Root and intermediate certificates only, excluding server certificate
- fullchain.pem : All certificates, including server certificate. This is concatenation of cert.pem and chain.pem
Then mount the volume like this :
mailserver:
image: hardware/mailserver
volumes:
- /mnt/docker/nginx/certs:/etc/letsencrypt
...
Postfix default configuration can be overrided providing a custom configuration file at postfix format. This can be used to also add configuration that are not in default configuration. Postfix documentation remains the best place to find configuration options.
Each line in the provided file will be loaded into Postfix. Create a new file here /mnt/docker/mail/postfix/custom.conf
and add your custom options inside.
Example :
# /mnt/docker/mail/postfix/custom.conf
smtpd_banner = $myhostname ESMTP MyGreatMailServer
inet_protocols = ipv4
delay_notice_recipient = admin@domain.tld
delay_warning_time = 2h
docker logs -f mailserver
[INFO] Override : smtpd_banner = $myhostname ESMTP MyGreatMailServer
[INFO] Override : inet_protocols = ipv4
[INFO] Override : delay_notice_recipient = postmaster@domain.tld
[INFO] Override : delay_warning_time = 2h
[INFO] Custom Postfix configuration file loaded
- IMAP/SMTP username : user@domain.tld
- Incoming IMAP server : mail.domain.tld (your FQDN)
- Outgoing SMTP server : mail.domain.tld (your FQDN)
- IMAP port : 993
- SMTP port : 587
- IMAP Encryption protocol : SSL/TLS
- SMTP Encryption protocol : STARTTLS
- Postfix 2.11.3
- Dovecot 2.2.13
- OpenDKIM 2.9.2
- OpenDMARC 1.3.0
- Spamassassin 3.4.0
- Postgrey 1.35
- Fetchmail 6.3.26
- ClamAV 0.98.7
- Amavisd-new 2.10.1
- Amavisd-milter 1.5.0
- Supervisor 3.0r1
- Rsyslog 8.4.2
- ManageSieve server
- Use Rspamd instead of Spamassassin
- ClueGetter integration
- LDAP authentification (need contributors)
- Fork this repository
- Create a new feature branch for a new functionality or bugfix
- Code...
- Add integration tests in test/tests.bats
- Use
maketo build image locally and run tests - Document your improvements
- Commit your changes
- Push your code and open a new pull request
- Use issues for any questions