aguslr/docker-postfix

This Docker image sets up Postfix inside a docker container.

Postfix is a free and open-source mail transfer agent (MTA) that routes and delivers electronic mail.

Installation

To use docker-postfix, follow these steps:

Clone and start the container:

docker run -p 25:25 \
  -e POSTFIX_HOSTNAME=mail.example.com \
  -e POSTFIX_RELAYSERVER=smtp.mail.com \
  -e POSTFIX_RELAYUSER=me@mail.com \
  -e POSTFIX_RELAYPASS=123456 \
  docker.io/aguslr/postfix:latest

Configure your systems to send email to your Postfix server's IP address on port 25.

Variables

The image is configured using environment variables passed at runtime. All these variables are prefixed by POSTFIX_.

Variable	Function	Required
`HOSTNAME`	Hostname for the container	Y
`DOMAIN`	Domain name for Postfix	N
`RELAYSERVER`	Address of the SMTP server to use	Y
`RELAYPORT`	Port to connect to the SMTP server	N
`RELAYUSER`	Username of SMTP server	Y
`RELAYPASS`	Password of SMTP server	N
`OVERWRITE`	Use this from address for all relayed emails	N
`FROM`	Rewrite from address	N
`TO`	Rewrite to address	N
`DESTINATION`	List of domains allowed to use relay server	N
`NETWORKS`	List of networks allowed to use relay server	N

Password file

As an alternative to passing the relay's server password at runtime, we can use a password file (e.g. passwd) with the format:

[RELAYSERVER]:RELAYPORT RELAYUSER:RELAYPASS

We can then mount this file at runtime with this command:

docker run -p 25:25 \
  -e POSTFIX_HOSTNAME=mail.example.com \
  -e POSTFIX_RELAYSERVER=smtp.mail.com \
  -e POSTFIX_RELAYUSER=me@mail.com \
  -v "${PWD}"/passwd:/etc/postfix/sasl_passwd \
  docker.io/aguslr/postfix:latest

Build locally

Instead of pulling the image from a remote repository, you can build it locally:

Clone the repository:

git clone https://github.com/aguslr/docker-postfix.git

Change into the newly created directory and use docker-compose to build and launch the container:
```
cd docker-postfix && docker-compose up --build -d
```