docker-postfix

A container running postfix intended to be used as an internal mail relay to the outside world.

Optionally authenticate incoming connections with SASL

Usage

docker

docker create \
  --name=posfix \
  -e PUID=1000 \
  -e PGID=1000 \
  -v </path/to/appdata/config>:/config \
  -p 25:25 \
  --restart unless-stopped \
  jchonig/postfix

docker-compose

Compatible with docker-compose v2 schemas.

---
version: "2"
services:
  postfix:
    image: jchonig/postfix
    environment:
      - PUID=1000
      - PGID=1000
    volumes:
      - </path/to/appdata/config>:/config
	  - data:/data
    port:
      - 25
    restart: unless-stopped

volumes:
  data:

Parameters

Ports (-p)

Volume	Function
25	The incoming SMTP port

Environment Variables (-e)

Env	Function
PUID=1000	for UserID - see below for explanation
PGID=1000	for GroupID - see below for explanation
USE_SASL=yes	Use sasl for user authentication
USE_SASLAUTHD=yes	Use saslauthd
USE_DKIM=yes	Not yet implemented
USE_TLS=yes	Enable STARTTLS for incoming connections on port 25
USE_SMTPS=yes	Enable TLS wrapper on port 465
MYHOSTNAME=example.com	Configure postfix myhostname parameter
MYORIGIN=example.com	Configure postfix myorigin parameter
MYDESTINATION=	Configure postfix mydestination parameter
MASQUERADE_DOMAINS=example.com	A comma seperated list of domains to masquerade
SMTPD_TLS_SECURITY_LEVEL=may	Configure the level of TLS required on incomming connections
BOUNCE_QUEUE_LIFETIME=1d	Configure the postfix bounce queue lifetime

Volume Mappings (-v)

Volume	Function
/data	Persistent data (i.e. /data/spool)
/config	All the config files reside here

Application Setup

• When USE_TLS is enabled, /config/server.cert and /config/server.key should exist
  • When these files are updated, postfix is reloaded automatically
• When using SASL, /config/sasl.users should should have one entry per line of user and password seperated by a space
  • WHen this file is updated, update_sasldb_users is run automatically
• Additonal postfix configuration can be stored in /config/postconf and /config/postconf.d/*
  • These files contain arguments to the postconf command
  • These files are processed when the container starts
  • These files are reparsed automatically when they are modified or created
  • The files in /config/postconf.d are not processed in a particular order
• Aliases are stored in /config/aliases
  • If this file does not exists the default postfix file is copied to it
  • When this file is updated, newaliases is run

TODO

• Set up DKIM
• Read and process generics and virtual? ...