tozd/postfix repository overview

⁠tozd/postfix

https://gitlab.com/tozd/docker/postfix⁠

Available as:

• tozd/postfix⁠
• registry.gitlab.com/tozd/docker/postfix⁠

⁠Image inheritance

tozd/base⁠ ← tozd/dinit⁠ ← tozd/postfix

⁠Tags

• ubuntu-trusty: Postfix 2.11.0
• ubuntu-xenial: Postfix 3.1.0
• ubuntu-bionic: Postfix 3.3.0
• ubuntu-focal: Postfix 3.4.13
• ubuntu-jammy: Postfix 3.6.4
• ubuntu-noble: Postfix 3.8.6
• alpine-38: Postfix 3.3.0
• alpine-310: Postfix 3.4.7
• alpine-312: Postfix 3.5.16
• alpine-314: Postfix 3.6.4
• alpine-316: Postfix 3.7.6
• alpine-318: Postfix 3.8.9
• alpine-320: Postfix 3.9.3
• alpine-322: Postfix 3.10.2

⁠Architectures

• amd64
• arm64

⁠Volumes

• /var/log/postfix: Log files when LOG_TO_STDOUT is not set to 1. Logs are not rotated on versions older than Postfix 3.4.
• /var/spool/postfix: Persist this volume to not lose state.

⁠Variables

• MAILNAME: /etc/mailname and myhostname⁠ Postfix configuration option are set to this value.
• MY_NETWORKS: mynetworks⁠ Postfix configuration option is set to this value. Default is 172.17.0.0/16 127.0.0.0/8.
• MY_DESTINATION: mydestination⁠ Postfix configuration option is set to this value. If you are not extending this Docker image to also deliver local (inside the container) e-mails then you generally do not have to change the default. Default is localhost.localdomain, localhost.
• ROOT_ALIAS: E-mail to which local (inside the container) e-mails to root user are send. If you are not extending this Docker image you generally do not have to set this as there are no e-mails send to the root user from inside the container.
• LOG_TO_STDOUT: If set to 1 output logs to stdout (retrievable using docker logs) instead of log volumes. Available for Postfix 3.4 and newer.

⁠Ports

• 25/tcp: SMTP port.
• 465/tcp: SMTPS port.
• 587/tcp: Mail submission port.

⁠Description

Docker image providing Postfix⁠.

You should make sure you mount spool volume (/var/spool/postfix) so that you do not lose e-mail data when you are recreating a container. If a volume is empty, image will initialize it at the first startup.

When LOG_TO_STDOUT is set to 1, Docker image logs output to stdout and stderr. All stdout output is JSON.

By default it is configured for sending outbound e-mails. Otherwise, you can extend the image and configure it differently. See these examples:

• cloyne/postfix⁠, which extends it to integrate it with tozd/sympa⁠ mailing lists service
• tozd/mail⁠, which extends it to provide a full-fledged e-mail service with virtual users

Remember that for the best e-mail delivery external IP should match the hostname it resolves to. You might find tozd/external-ip⁠ Docker image useful for this.

If you are extending this image, you can add two scripts which will be run at a container startup:

• /etc/service/postfix/run.config – to prepare any custom configuration, before anything else is run
• /etc/service/postfix/run.initialization – will be run after the container is initialized, but before the Postfix daemon is run

If you just need programs inside your Docker images to send e-mails using sendmail program locally, consider using tozd/mailer⁠ or tozd/nginx-mailer⁠ Docker image as your base. This tozd/postfix Docker image delivers e-mails to wide Internet by itself. Then you can configure tozd/mailer-based containers to relay e-mails to one tozd/postfix container which then sends e-mails out.

⁠Alpine Linux image notes

• Alpine Linux does not support hash or btree lookup tables⁠
• Use lmdb type databases instead for example:
  • virtual_alias_maps = lmdb:/etc/postfix/virtual

⁠GitHub mirror

There is also a read-only GitHub mirror available⁠, if you need to fork the project there.