docker-mailserver

by tomav

A fullstack but simple mailserver (smtp, imap, antispam, antivirus, ssl...) using Docker.

6.1K Stars 988 Forks Last release: 29 days ago (v7.1.0) MIT License 1.0K Commits 35 Releases

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docker-mailserver

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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.

Why was this image was created?

  1. Announcements
  2. Includes
  3. Issues & Contributing
  4. Requirements
  5. Usage
  6. Examples
  7. Environment Variables

Announcements

  1. Since version
    v7.1.0
    , the use of default variables has changed slightly. Please consult the environment Variables sections
  2. Debian Buster is now Docker base image
    • Filebeat was removed
    • Dovecot was downgraded
  3. ELK was removed
  4. New contributing guidelines were added
  5. Added coherent coding style and linting
  6. Added option to use non-default network interface

Includes

Issues & Contributing

Before opening an issue, please have a look this

README
, the Wiki and the Postfix/Dovecot documentation.

If you'd like to contribute, read

CONTRIBUTING.md
thoroughly.

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.

Usage

Get the tools

Download the

docker-compose.yml
,
.env
,
env-mailserver
and the
setup.sh
files:
wget https://raw.githubusercontent.com/tomav/docker-mailserver/master/setup.sh
wget https://raw.githubusercontent.com/tomav/docker-mailserver/master/docker-compose.yml
wget https://raw.githubusercontent.com/tomav/docker-mailserver/master/env-mailserver
curl -o .env https://raw.githubusercontent.com/tomav/docker-mailserver/master/template.env

chmod a+x ./setup.sh

Create a docker-compose environment

  • Install the latest docker-compose
  • Edit the files
    .env
    and
    env-mailserver
    to your liking:
    • .env
      contains the configuration for docker-compose
    • env-mailserver
      contains the configuration for the mailserver container
    • These files supports only simple
      VAR=VAL
      lines (see Documentation).
    • Don't quote your values.
    • Variable substitution is not supported (e.g.
      OVERRIDE_HOSTNAME=$HOSTNAME.$DOMAINNAME
      ).

Note:: Variables in

.env
are expanded in the
docker-compose.yml
file only and not in the container. The file
env-mailserver
serves this case where environment variables are used in the container.

Note: If you want to use a bare domain (host name equals domain name) see FAQ.

Get up and running

docker-compose up -d mail
./setup.sh email add  []
./setup.sh config dkim

Now that 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.

Miscellaneous

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 with
./setup.sh -h
.

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.

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 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. Originally a secure variant of port 25.

See the wiki for further details and best practice advice, especially regarding security concerns.

Examples

With Relevant Environmental Variables

version: '3.8'

services: mail: image: tvial/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 cap_add: - NET_ADMIN - SYS_PTRACE restart: always

volumes: maildata: mailstate: maillogs:

LDAP setup

version: '3.8'

services: mail: image: tvial/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)) - [email protected] - POSTFIX_MESSAGE_SIZE_LIMIT=100000000 cap_add: - NET_ADMIN - SYS_PTRACE restart: always

volumes: maildata: mailstate: maillogs:

Environment variables

If an option doesn't work as documented here, check if you are running the latest image! Values in bold are the default values.

Note: Since

docker-mailserver v7.1.0
, comparisons for environment variables are executed differently. If you previously used
VARIABLE=''
as the
empty
value, please update to now use
VARIABLE=
.

Assignments

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
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) WARNING: Adding the docker network's gateway to the list of trusted hosts, e.g. using the

network
or
connected-networks
option, can create an open relay, for instance if IPv6 is enabled on the host machine but not in Docker.
  • 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) use
    PERMIT_DOCKER=connected-networks
    in this case
  • connected-networks => Add all connected docker networks (ipv4 only)

Note: you probably want to set

POSTFIX_INET_PROTOCOLS=ipv4
to make it work fine with Docker.

NETWORK_INTERFACE

In case your network interface differs from

eth0
, e.g. when you are using HostNetworking in Kubernetes, you can set this to whatever interface you want. This interface will then be used.
  • empty =>
    eth0
VIRUSMAILSDELETEDELAY

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

  • empty => 7 days
ENABLEPOSTFIXVIRTUAL_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 ENABLEPOSTFIXVIRTUAL_TRANSPORT. Specify the final delivery of postfix

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)
ENABLE_QUOTAS
  • 1 => Dovecot quota is enabled
  • 0 => Dovecot quota is disabled

See mailbox quota.

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
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.
DOVECOTMAILBOXFORMAT
  • maildir => uses very common Maildir format, one file contains one message
  • sdbox => (experimental) uses Dovecot high-performance mailbox format, one file contains one message
  • mdbox ==> (experimental) uses Dovecot high-performance mailbox format, multiple messages per file and multiple files per box

This option has been added in November 2019. Using other format than Maildir is considered as experimental in docker-mailserver and should only be used for testing purpose. For more details, please refer to Dovecot Documentation.

POSTFIXINETPROTOCOLS
  • all => All possible protocols.
  • ipv4 => Use only IPv4 traffic. Most likely you want this behind Docker.
  • ipv6 => Use only IPv6 traffic.

Note: More details in http://www.postfix.org/postconf.5.html#inet_protocols

Reports

PFLOGSUMM_TRIGGER

Enables regular pflogsumm mail reports.

  • not set => No report
  • daily_cron => Daily report for the previous day
  • logrotate => Full report based on the mail log when it is rotated

This is a new option. The old REPORT options are still supported for backwards compatibility. If this is not set and reports are enabled with the old options, logrotate will be used.

PFLOGSUMM_RECIPIENT

Recipient address for pflogsumm reports.

  • not set => Use REPORTRECIPIENT or POSTMASTERADDRESS
  • => Specify the recipient address(es)
PFLOGSUMM_SENDER

From address for pflogsumm reports.

  • not set => Use REPORTSENDER or POSTMASTERADDRESS
  • => Specify the sender address
LOGWATCH_INTERVAL

Interval for logwatch report.

  • none => No report is generated
  • daily => Send a daily report
  • weekly => Send a report every week
LOGWATCH_RECIPIENT

Recipient address for logwatch reports if they are enabled.

  • not set => Use REPORTRECIPIENT or POSTMASTERADDRESS
  • => Specify the recipient address(es)
REPORT_RECIPIENT (deprecated)

Enables a report being sent (created by pflogsumm) on a regular basis.

  • 0 => Report emails are disabled unless enabled by other options
  • 1 => Using POSTMASTER_ADDRESS as the recipient
  • => Specify the recipient address
REPORT_SENDER (deprecated)

Change the sending address for mail report

REPORT_INTERVAL (deprecated)

Changes the interval in which logs are rotated and a report is being sent (deprecated).

  • daily => Send a daily report
  • weekly => Send a report every week
  • monthly => Send a report every month

Note: This variable used to control logrotate inside the container and sent the pflogsumm report when the logs were rotated. It is still supported for backwards compatibility, but the new option LOGROTATE_INTERVAL has been added that only rotates the logs.

LOGROTATE_INTERVAL

Defines the interval in which the mail log is being rotated.

  • daily => Rotate daily.
  • weekly => Rotate weekly.
  • monthly => Rotate monthly.

Note that only the log inside the container is affected. The full log output is still available via

docker logs mail
(or your respective container name). If you want to control logrotation for the docker generated logfile see: Docker Logging Drivers.

Also note that by default the logs are lost when the container is recycled. To keep the logs, mount a volume.

Finally the logrotate interval may affect the period for generated reports. That is the case when the reports are triggered by log rotation.

Spamassassin

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

/!\ Spam delivery: when Spamassassin is enabled, messages marked as spam WILL NOT BE DELIVERED. Use

SPAMASSASSIN_SPAM_TO_INBOX=1
for receiving spam messages.
SPAMASSASSINSPAMTO_INBOX
  • 0 => Spam messages will be bounced (rejected) without any notification (dangerous).
  • 1 => Spam messages will be delivered to the inbox and tagged as spam using
    SA_SPAM_SUBJECT
    .
MOVESPAMTO_JUNK
  • 1 => Spam messages will be delivered in the
    Junk
    folder.
  • 0 => Spam messages will be delivered in the mailbox.

Note: this setting needs

SPAMASSASSIN_SPAM_TO_INBOX=1
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 ONEDIR setting above. If `ONEDIR=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.
SASPAMSUBJECT
  • ***SPAM*** => add tag to subject if spam detected

Note: this spamassassin setting needs

ENABLE_SPAMASSASSIN=1
. Add the spamassassin score to the subject line by inserting the keyword SCORE: ***SPAM(SCORE)***.
SASHORTCIRCUITBAYES_SPAM
  • 1 => will activate spamassassin short circuiting for bayes spam detection.

This will uncomment the respective line in

/etc/spamassasin/local.cf

Note: activate this only if you are confident in your bayes database for identifying spam.

SASHORTCIRCUITBAYES_HAM
  • 1 => will activate spamassassin short circuiting for bayes ham detection

This will uncomment the respective line in

/etc/spamassasin/local.cf

Note: activate this only if you are confident in your bayes database for identifying ham.

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
LDAPSTARTTLS
  • empty => no
  • yes => LDAP over TLS enabled for Postfix
LDAPSERVERHOST
  • 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
LDAPSEARCHBASE
  • empty => ou=people,dc=domain,dc=com
  • => e.g. LDAPSEARCHBASE=dc=mydomain,dc=local
LDAPBINDDN
  • empty => cn=admin,dc=domain,dc=com
  • => take a look at examples of SASLLDAPBIND_DN
LDAPBINDPW
  • empty => admin
  • => Specify the password to bind against ldap
LDAPQUERYFILTER_USER
  • e.g.
    (&(mail=%s)(mailEnabled=TRUE))
  • => Specify how ldap should be asked for users
LDAPQUERYFILTER_GROUP
  • e.g.
    (&(mailGroupMember=%s)(mailEnabled=TRUE))
  • => Specify how ldap should be asked for groups
LDAPQUERYFILTER_ALIAS
  • e.g.
    (&(mailAlias=%s)(mailEnabled=TRUE))
  • => Specify how ldap should be asked for aliases
LDAPQUERYFILTER_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
.
DOVECOTUSERFILTER
  • e.g.
    (&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n))
DOVECOTUSERATTRS
  • 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
DOVECOTPASSFILTER
  • e.g.
    (&(objectClass=PostfixBookMailAccount)(uniqueIdentifier=%n))
DOVECOTPASSATTRS
  • 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
POSTGREYMAXAGE
  • 35 => delete entries older than N days since the last time that they have been seen

Note: This postgrey setting needs

ENABLE_POSTGREY=1
POSTGREYAUTOWHITELIST_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 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
SASLAUTHDMECHOPTIONS
  • empty => None
  • e.g. with SASLAUTHD_MECHANISMS rimap you need to specify the ip-address/servername of the imap server ==> xxx.xxx.xxx.xxx
SASLAUTHDLDAPSERVER
  • empty => localhost
SASLAUTHDLDAPSSL
  • empty or 0 =>
    ldap://
    will be used
  • 1 =>
    ldaps://
    will be used
SASLAUTHDLDAPBIND_DN
  • empty => anonymous bind
  • specify an object with privileges to search the directory tree
  • e.g. active directory: SASLAUTHDLDAPBIND_DN=cn=Administrator,cn=Users,dc=mydomain,dc=net
  • e.g. openldap: SASLAUTHDLDAPBIND_DN=cn=admin,dc=mydomain,dc=net
SASLAUTHDLDAPPASSWORD
  • empty => anonymous bind
SASLAUTHDLDAPSEARCH_BASE
  • empty => Reverting to SASLAUTHD_MECHANISMS pam
  • specify the search base
SASLAUTHDLDAPFILTER
  • 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)

SRSSENDERCLASSES

An email has an "envelope" sender (indicating the sending server) and a "header" sender (indicating who sent it). More strict SPF policies may require you to replace both instead of just the envelope sender.

More info.

  • envelope_sender => Rewrite only envelope sender address
  • header_sender => Rewrite only header sender (not recommended)
  • envelopesender,headersender => Rewrite both senders
SRSEXCLUDEDOMAINS
  • 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

DEFAULTRELAYHOST
  • empty => don't set default relayhost setting in main.cf
  • default host and port to relay all mail through. Format:
    [example.com]:587
    (don't forget the brackets if you need this to be compatible with
    $RELAY_USER
    and
    $RELAY_PASSWORD
    , explained below).

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

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