postfix

Postfix mail server container.

Summary

• Dockerfile.DOVECOT - build container image with dovecot w/o postfix.
• Dockerfile.POSTFIX - build container image with postfix w/o dovecot.
• Dockerfile.IMAP - build container image with dovecot and postfix installed. Full IMAP server.
• Dockerfile.TLS - build container image with postfix TLS enabled w/o dovecot.
• imap-template.yml - Template for OpenShift to start IMAP server with two containers (postfix and dovecot)

How to build the container on 25 port

docker build --tag=postfix .

How to build the container with TLS enabled

docker build -f Docker.TLS --tag=postfix .

How to build the container with dovecot service

docker build -f Docker.IMAP --tag=postfix .

How to use the container over standard 25 port

Command for running postfix docker container:

docker run -it -e MYHOSTNAME=localhost \
    -p 25:10025\
    -v $(pwd)/tmp/postfix:/var/spool/postfix \
    -v $(pwd)/tmp/mail:/var/spool/mail postfix

How to use the container over standard TLS

Dockerfile for TLS port is Dockerfile.TLS.

Command for running postfix docker container:

docker run -it -e DEBUG_MODE=yes -e MYHOSTNAME=localhost \
    -p 25:10025 \
    postfix

Environment variable DEBUG_MODE is used for debugging proposes from Postfix and dovecot point of views.

How to use the container with IMAP with TLS enabled (dovecot and Postfix)

Dockerfile which uses IMAP is Dockerfile.IMAP.

Command for running postfix docker container:

docker run -it -e MYHOSTNAME=localhost -e DEBUG_MODE \
    -p 25:10025 -p 587:10587 -p 143:10143 \
    postfix

Environment variable DEBUG_MODE is used for debugging proposes from Postfix and dovecot point of views.

Docker container does NOT share user from HOST system. Therefore I prefer to create users in container. This is not yet automated. Will be SOON.

Steps are:

docker exec -n postfix /bin/bash /file/create_user.sh <user_name>

Now the user can be used for mail clients.

How to test the postfix mail server

Commands for testing Postfix docker container:

telnet localhost 25

HELO test.localhost

MAIL FROM:<yourname>@<domain.com>

RCPT TO:<demo@localhost>

DATA and type whatever you want

Subject: My testing docker container image

Hi, Testing message
regards
Docker
.

How to test the postfix mail server with TLS

Command for testing Postfix docker container with enabled TLS is openssl.

Telnet has not to be used because of all communication is encrypted from the beginning.

openssl s_client -starttls smtp -crlf -connect localhost:25

How to test the postfix with dovecot service

Command for testing Postfix docker container with dovecot is openssl.

Telnet has not to be used because of all communication is encrypted from the beginning.

Testing dovecot service with openssl

openssl s_client -starttls imap -connect localhost:143

Testing postfix service with openssl

openssl s_client -debug -starttls smtp -crlf -connect localhost:25