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Postfix SMTP only with relay support

Postfix SMTP only Docker image with SMTP relay support.

  • CentOS: 7
  • Postfix: 2.10.1
  • Expose: 25

Supported tags and respective Dockerfile links

Stable and immutable tags

  • :2.10-3.7 Dockerfile - Postfix: 2.10 Release: 3.7

See older versions

Base docker image

Source code


Start postfix (to send emails using postfix within container)

$ docker run --rm --name=postfix \
             -e \

or start postfix (to send emails by using a remote email server)

$ docker run --rm --name=postfix \
             -e \
             -e \
             -e MTP_USER=foo \
             -e MTP_PASS=secret \

Start sending emails:

$ docker run -it --rm --link=postfix busybox sh
  $ telnet postfix 25
  MAIL FROM: [email protected]
  RCPT TO: [email protected]
  subject: Test
  Testing 1, 2, 3

Supported environment variables

  • MTP_HOST The myhostname parameter specifies the internet hostname of this mail system
  • MTP_DESTINATION The mydestination parameter specifies the list of domains that this machine considers itself the final destination for.
  • MTP_BANNER The smtpd_banner parameter specifies the text that follows the 220 code in the SMTP server's greeting banner.
  • MTP_RELAY The relayhost parameter specifies the default host to send mail to when no entry is matched in the optional transport(5) table.
  • MTP_RELAY_DOMAINS The relay_domains parameter restricts what destinations this system will relay mail to.
  • MTP_PORT The relayhost port.
  • MTP_USER The user used to connect to the relayhost.
  • MTP_PASS The password used to connect to the relayhost.
  • MTP_INTERFACES The inet_interfaces parameter specifies the network interface addresses that this mail system receives mail on.
  • MTP_PROTOCOLS The inet_protocols parameter specifies the network interface protocol. Can be set to all, ipv4,ipv6 or ipv4,ipv6. The default value is all.
  • MTP_MS_SIZE_LIMIT If set, will configure email size limit.

Copyright and license

The Initial Owner of the Original Code is European Environment Agency (EEA). All Rights Reserved.

The Original Code is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.


European Environment Agency (EU)

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