cedricroijakkers/postfix-docker repository overview

⁠About postfix-docker

This container runs the postfix mail server, and is a combination of the following two containers:

• https://github.com/jessfraz/dockerfiles/tree/master/postfix⁠
• https://github.com/juanluisbaptiste/docker-postfix⁠

It combines both into one, using the alpine base and logging from the first container; and the configuration properties from the second.

It allows to run an SMTP server in a docker container, which can relay mails via another upstream SMTP server. Optionally, you can specify a user name and password for the upstream server, and this container will take care of the authentication. This container can be used when you want to have a single mail queue, and do not want to configure SMTP authentication in your application, but want this container to handle that for you.

⁠How to run it

The following env variables are mandatory to be passed to the container:

• SMTP_SERVER: Server address of the upstream SMTP server to use.
• SERVER_HOSTNAME: Server hostname for the Postfix container. Emails will appear to come from the hostname's domain.

The following env variables are optional, if you upstream server uses authentication:

• SMTP_USERNAME: Username to authenticate with.
• SMTP_PASSWORD: Password of the SMTP user.

The following env variable(s) are optional.

• SMTP_PORT: (Default value: 25) Port number of the upstream SMTP server to use.
• RECIPIENT_LIMIT: (Default value: 1000) Maximum number of recipients per mail.
• SMTP_HEADER_TAG: When set, will add a header for tracking messages upstream. Helpful for spam filters. Will appear as RelayTag: ${SMTP_HEADER_TAG} in the email headers.
• REWRITE_DOMAIN: When set, will change the part behind the @ character in all from-adresses to the specified domain, this is handy when your upstream server requires mails to be sent from a specific domain only (do not add the @ character itself).

To use this container from anywhere, the 25 port needs to be exposed to the docker host server:

To configure an upstream server without authentication:

docker run -d --name postfix -p "25:25"  \ 
       -e SMTP_SERVER=smtp.bar.com \
       -e SERVER_HOSTNAME=helpdesk.mycompany.com \
       cedricroijakkers/postfix-docker:3.4.7

To configure an upstream server with authentication:

docker run -d --name postfix -p "25:25"  \ 
       -e SMTP_SERVER=smtp.bar.com \
       -e SERVER_HOSTNAME=helpdesk.mycompany.com \
       -e [email protected] \
       -e SMTP_PASSWORD=XXXXXXXX \
       cedricroijakkers/postfix-docker:3.4.7

⁠Maintainer

This container is built and maintained by Cedric Roijakkers⁠.