Postfix MTA with TLS encryption and DKIM in Docker container

Simple in usage isolated SMTP server

Link on Docker Hub

https://hub.docker.com/r/terenchukv/postfix/

REQUIREMENTS

• Docker
• Docker compose

INSTALLATION

• clone this repo
• copy and edit .env file with yours variables

cp .env.dist .env

• For example your domain: mail.example.com

MAIL_HOST=mail    <--- container hostname
MAIL_DOMAIN=example.com  <--- domain name which point A record to your host
MAIL_SENDERS=mail.example.com <--- MAIL_HOST + MAIL_DOMAIN
SENDER_HOST=mail.example.com  <--- MAIL_HOST + MAIL_DOMAIN
CERT_COUNTRY=Ukraine
CERT_STATE=Kiev
CERT_CITY=Kiev
CERT_COMPANY=my_awsome_company

• build docker container

docker-compose build

• start container

docker-compose up -d

• NOTE! If you use firewall open 25 port. For example:

iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j ACCEPT

• Find DKIM record in /var/db/dkim/your_domain/default.txt and add this record in yor domain registrator

docker exec -it mail sh -c "cat /var/db/dkim/your_domain/default.txt"

TEST SMTP

• connect to container

docker exec -it mail sh

• send test mail

echo 'Subject: test' | /usr/sbin/sendmail your_mail@test.com