22 KiB
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
- postscreen
- postgrey
- basic sieve support using dovecot
- LetsEncrypt and self-signed certificates
- setup script to easily configure and maintain your mailserver
- 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.
Requirements
Recommended:
- 1 CPU
- 1GB RAM
Minimum:
- 1 CPU
- 512MB RAM
Note: You'll need to deactivate some services like ClamAV to be able to run on a host with 512MB of RAM.
Usage
Get latest image
docker pull tvial/docker-mailserver:latest
Get the tools
Download the docker-compose.yml, the .env and the setup.sh files:
curl -o setup.sh https://raw.githubusercontent.com/tomav/docker-mailserver/master/setup.sh; chmod a+x ./setup.sh
curl -o docker-compose.yml https://raw.githubusercontent.com/tomav/docker-mailserver/master/docker-compose.yml.dist
curl -o .env https://raw.githubusercontent.com/tomav/docker-mailserver/master/.env.dist
Create a docker-compose environment
- Edit the
.env
to your liking. Adapt this file with your FQDN.- This file supports only simple
VAR=VAL
lines (see Documentation). - Don't quote your values.
- Variable substitution is not supported (e.g.
OVERRIDE_HOSTNAME=$HOSTNAME.$DOMAINNAME
).
- This file supports only simple
- Install docker-compose in the version
1.7
or higher.
Start Container
docker-compose up -d mail
Create your mail accounts
./setup.sh email add <user@domain> [<password>]
Generate DKIM keys
./setup.sh config dkim
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.
Restart and update the container
docker-compose down
docker pull tvial/docker-mailserver:latest
docker-compose up -d mail
You're done!
And don't forget to have a look at the remaining functions of the setup.sh
script
SPF/Forwarding Problems
If you got any problems with SPF and/or forwarding mails, give SRS a try. You enable SRS by setting ENABLE_SRS=1
. See the variable description for further information.
For informational purposes:
Your config folder will be mounted in /tmp/docker-mailserver/
. To understand how things work on boot, please have a look at 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.
Exposed ports
- 25 receiving email from other mailservers
- 465 SSL Client email submission
- 587 TLS Client email submission
- 143 StartTLS IMAP client
- 993 TLS/SSL IMAP client
- 110 POP3 client
- 995 TLS/SSL POP3 client
Note: Port 25 is only for receiving email from other mailservers and not for submitting email. You need to use port 465 or 587 for this.
Examples with just the relevant environmental variables:
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
- SYS_PTRACE
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)(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
- POSTMASTER_ADDRESS=postmaster@localhost.localdomain
- POSTFIX_MESSAGE_SIZE_LIMIT=100000000
cap_add:
- NET_ADMIN
- SYS_PTRACE
volumes:
maildata:
driver: local
mailstate:
driver: local
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.
General
DMS_DEBUG
- 0 => Debug disabled
- 1 => Enables debug on startup
ENABLE_CLAMAV
- 0 => Clamav is disabled
- 1 => Clamav is enabled
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.
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 you manually specify locations of your SSL certificates for non-standard cases
- self-signed => Enables self-signed certificates
- any other value => SSL required, settings by default
Please read the SSL page in the wiki for more information.
TLS_LEVEL
- empty => modern
- modern => Enables TLSv1.2 and modern ciphers only. (default)
- intermediate => Enables TLSv1, TLSv1.1 and TLSv1.2 and broad compatibility ciphers.
- old => NOT implemented. If you really need it, then customize the TLS ciphers overriding postfix and dovecot settings [ wiki](https://github.com/tomav/docker-mailserver/wiki/
SPOOF_PROTECTION
Configures the handling of creating mails with forged sender addresses.
- empty => Mail address spoofing allowed. Any logged in user may create email messages with a forged sender address. See also Wikipedia(not recommended, but default for backwards compatibility reasons)
- 1 => (recommended) Mail spoofing denied. Each user may only send with his own or his alias addresses. Addresses with extension delimiters are not able to send messages.
ENABLE_SRS
Enables the Sender Rewriting Scheme. SRS is needed if your mail server acts as forwarder. See postsrsd for further explanation.
- 0 => Disabled
- 1 => Enabled
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 the docker default bridge network (172.16.0.0/12); WARNING:
docker-compose
might use others (e.g. 192.168.0.0/16) usePERMIT_DOCKER=connected-networks
in this case - connected-networks => Add all connected docker networks (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.
POSTFIX_MAILBOX_SIZE_LIMIT
Set the mailbox size limit for all users. If set to zero, the size will be unlimited (default).
- empty => 0 (no limit)
POSTFIX_MESSAGE_SIZE_LIMIT
Set the message size limit for all users. If set to zero, the size will be unlimited (not recommended!)
- empty => 10240000 (~10 MB)
ENABLE_MANAGESIEVE
- empty => Managesieve service disabled
- 1 => Enables Managesieve on port 4190
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
POSTSCREEN_ACTION
- enforce => Allow other tests to complete. Reject attempts to deliver mail with a 550 SMTP reply, and log the helo/sender/recipient information. Repeat this test the next time the client connects.
- drop => Drop the connection immediately with a 521 SMTP reply. Repeat this test the next time the client connects.
- ignore => Ignore the failure of this test. Allow other tests to complete. Repeat this test the next time the client connects. This option is useful for testing and collecting statistics without blocking mail.
REPORT_RECIPIENT
Enables a report being sent (created by pflogsumm) on a regular basis.
- 0 => Report emails are disabled
- 1 => Using POSTMASTER_ADDRESS as the recipient
- => Specify the recipient address
REPORT_SENDER
Change the sending address for mail report
- empty => mailserver-report@hostname
- => Specify the report sender (From) address
REPORT_INTERVAL
changes the interval in which a report is being sent.
- daily => Send a daily report
- weekly => Send a report every week
- monthly => Send a report every month
Note: This Variable actually controls logrotate inside the container and rotates the log depending on this setting. The main log output is still available in its entirety via docker logs mail
(Or your respective container name). If you want to control logrotation for the docker generated logfile see: Docker Logging Drivers
Spamassassin
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
. By default, the mailserver is configured to quarantine spam emails. If emails are quarantined, they are compressed and stored in a location dependent on the ONE_DIR setting above. If ONE_DIR=1
the location is /var/mail-state/lib-amavis/virusmails/. If ONE_DIR=0
it is /var/lib/amavis/virusmails/. These paths are inside the docker container. To inhibit this behaviour and deliver spam emails, set this to a very high value e.g. 100.0.
SA_SPAM_SUBJECT
- ***SPAM*** => add tag to subject if spam detected
Note: this spamassassin setting needs ENABLE_SPAMASSASSIN=1
Fetchmail
ENABLE_FETCHMAIL
- 0 =>
fetchmail
disabled - 1 =>
fetchmail
enabled
FETCHMAIL_POLL
- 300 =>
fetchmail
The number of seconds for the interval
LDAP
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 container this article may be helpful
LDAP_START_TLS
- empty => no
- yes => LDAP over TLS enabled for Postfix
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
LDAP_QUERY_FILTER_DOMAIN
- e.g.
(&(|(mail=*@%s)(mailalias=*@%s)(mailGroupMember=*@%s))(mailEnabled=TRUE))
- => Specify how ldap should be asked for domains
DOVECOT_TLS
- empty => no
- yes => LDAP over TLS enabled for Dovecot
Dovecot
The following variables overwrite the default values for /etc/dovecot/dovecot-ldap.conf.ext
.
DOVECOT_USER_FILTER
- e.g.
(&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n))
DOVECOT_USER_ATTRS
- e.g.
homeDirectory=home,qmailUID=uid,qmailGID=gid,mailMessageStore=mail
- => Specify the directory to dovecot attribute mapping that fits your directory structure.
- Note: This is necessary for directories that do not use the Postfix Book Schema.
- Note: The left-hand value is the directory attribute, the right hand value is the dovecot variable.
- More details on the Dovecot Wiki
DOVECOT_PASS_FILTER
- e.g.
(&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n))
DOVECOT_PASS_ATTRS
- e.g.
uid=user,userPassword=password
- => Specify the directory to dovecot variable mapping that fits your directory structure.
- Note: This is necessary for directories that do not use the Postfix Book Schema.
- Note: The left-hand value is the directory attribute, the right hand value is the dovecot variable.
- More details on the Dovecot Wiki
Postgrey
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_AUTO_WHITELIST_CLIENTS
- 5 => whitelist host after N successful deliveries (N=0 to disable whitelisting)
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
SASL Auth
ENABLE_SASLAUTHD
- 0 =>
saslauthd
is disabled - 1 =>
saslauthd
is enabled
SASLAUTHD_MECHANISMS
- empty => pam
ldap
=> authenticate against ldap servershadow
=> authenticate against local user dbmysql
=> authenticate against mysql dbrimap
=> 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 privileges 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
SRS (Sender Rewriting Scheme)
SRS_EXCLUDE_DOMAINS
- empty => Envelope sender will be rewritten for all domains
- provide comma separated list of domains to exclude from rewriting
SRS_SECRET
- empty => generated when the container is started for the first time
- provide a secret to use in base64
- you may specify multiple keys, comma separated. the first one is used for signing and the remaining will be used for verification. this is how you rotate and expire keys
- if you have a cluster/swarm make sure the same keys are on all nodes
- example command to generate a key:
dd if=/dev/urandom bs=24 count=1 2>/dev/null | base64
SRS_DOMAINNAME
- empty => Derived from OVERRIDE_HOSTNAME, DOMAINNAME, or the container's hostname
- Set this if auto-detection fails, isn't what you want, or you wish to have a separate container handle DSNs
Default Relay Host
DEFAULT_RELAY_HOST
- empty => don't set default relayhost setting in main.cf
- default host and port to relay all mail through
Multi-domain Relay Hosts
RELAY_HOST
- empty => don't configure relay host
- default host to relay mail through
RELAY_PORT
- empty => 25
- default port to relay mail through
RELAY_USER
- empty => no default
- default relay username (if no specific entry exists in postfix-sasl-password.cf)
RELAY_PASSWORD
- empty => no default
- password for default relay user