eeacms/postfix repository overview

⁠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

• :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 – Defines the myhostname value, representing the public internet hostname of this mail system.
• MTP_DESTINATION – Sets mydestination, the list of domains for which this host is considered the final mail destination.
• MTP_BANNER – Configures smtpd_banner, the text displayed after the 220 response in the SMTP greeting.
• MTP_RELAY – Specifies relayhost, the default server used to forward outgoing mail when no transport rule matches. (If used
• MTP_RELAY_DOMAINS – Limits the set of destination domains for which this system is allowed to relay mail.
• MTP_PORT – Defines the port used when connecting to the relay host.
• MTP_USER – Username used to authenticate with the relay host.
• MTP_PASS – Password used to authenticate with the relay host.
• MTP_RELAY, MTP_PORT, MTP_USER, and MTP_PASS are interdependent and must be defined together. If any of them is missing, the relay configuration will not function.
• MTP_INTERFACES – Sets inet_interfaces, controlling the network interfaces on which Postfix listens for incoming mail.
• MTP_PROTOCOLS – Sets inet_protocols, specifying the IP protocol(s) to use (all, ipv4, ipv6, or ipv4,ipv6; default: all).
• MTP_MS_SIZE_LIMIT – When defined, configures the maximum allowed email size.
• SMTPD_TLS_SECURITY_LEVEL – TLS security level for the Postfix SMTP server (default: none; values: none, may – opportunistic TLS, encrypt – mandatory TLS).
• SMTP_TLS_SECURITY_LEVEL – TLS security level for the Postfix SMTP client (default: may; values: none, may – opportunistic TLS, encrypt – mandatory TLS).

⁠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)⁠