Postfix SMTP only with relay support

Postfix SMTP only Docker image with SMTP relay support.

• Rocky Linux: 9.3
• Postfix: 3.5.25
• Expose: 25

Supported tags and respective Dockerfile links

Important

Starting with the release 3.5-1.0, the MTP_USER and MTP_PASS variables became mandatory, as without them, emails are rejected as SPAM and are not sent

• :latest Dockerfile - Rocky Linux: 9.3 Postfix: 3.5.25
• :3.5-1.1 Dockerfile - Rocky Linux: 9.3 Postfix: 3.5.25
• :3.5-1.0 Dockerfile - Rocky Linux: 9.3 Postfix: 3.5.9
• :2.10-3.8 Dockerfile - CentOS: 7 Postfix: 2.10.1

See older versions

Base docker image

• hub.docker.com

Source code

• github.com

Usage

Start postfix (to send emails using postfix within container)

$ docker run --rm --name=postfix \
             -e  MTP_HOST=foo.com \
         eeacms/postfix

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

$ docker run --rm --name=postfix \
             -e MTP_HOST=foo.com \
             -e MTP_RELAY=smtp.gmail.com \
             -e MTP_USER=foo \
             -e MTP_PASS=secret \
         eeacms/postfix

Start sending emails:

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

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.
• SMTPD_TLS_SECURITY_LEVEL The SMTP TLS security level for the Postfix SMTP server. Default value: none. Possible values: none(TLS will not be used), may( Opportunistic TLS), encrypt(Mandatory TLS encryption)
• SMTP_TLS_SECURITY_LEVEL The default SMTP TLS security level for the Postfix SMTP client. Default value: may. Possible values: none(TLS will not be used), may( Opportunistic TLS), encrypt(Mandatory TLS encryption)

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.

Funding

European Environment Agency (EU)