docker-smtp-sink

A minimalist fake SMTP server for development and debugging purposes.

This is running in docker using docker-compose and is based on https://github.com/Tecnativa/docker-smtp-sink augmented with graceful stop for docker containers and rename email messages to .eml files.

Usage

Create ./tmp/mail directory and let smtp-sink container save .eml files there:

version: '3.2'

services:
  smtp-sink:
    container_name: smtp-sink
    image: zanne/smtp-sink
    restart: unless-stopped
    volumes:
      - ./tmp/mail:/tmp/mail
    ports:
      - 8025:25

Notes

If this is used with PHP library PHPMailer use following settings:

$mailer->SMTPDebug = 0;
$mailer->SMTPAuth = false;
$mailer->SMTPSecure = '';

Example

Use example docker-compose.yml to run server locally on port 8025 (create tmp/mail directory) and test it using telnet by runing telnet localhost 8025 and pasting following commands to the server:

EHLO test.com
MAIL FROM: <[email protected]>
RCPT TO: <[email protected]>
DATA
Subject: test

This is a test message.
.
QUIT

You should get following output from the server:

250-smtp-sink
250-PIPELINING
250-8BITMIME
250-AUTH PLAIN LOGIN
250-XCLIENT NAME HELO
250-XFORWARD NAME ADDR PROTO HELO
250-ENHANCEDSTATUSCODES
250-DSN
250
250 2.1.0 Ok
250 2.1.5 Ok
354 End data with <CR><LF>.<CR><LF>
250 2.0.0 Ok
221 Bye
Connection closed by foreign host.

And caught email message will be saved in tmp/mail directory.

Docker Image

Pull from Docker Hub registry:

docker pull zanne/smtp-sink:latest