Install mailcow

WARNING: Please use Ubuntu 16.04 instead of Debian 8 or switch to the kernel 4.9 from jessie backports because there is a bug (kernel panic) with the kernel 3.16 when running docker containers with healthchecks! Full details here: github.com/docker/docker/issues/30402 and forum.mailcow.email/t/solved-mailcow-docker-causes-kernel-panic-edit/448

You need Docker and Docker Compose.

1. Learn how to install Docker and Docker Compose.

Quick installation for most operation systems:

  • Docker
curl -sSL https://get.docker.com/ | sh
  • Docker-Compose
curl -L https://github.com/docker/compose/releases/download/$(curl -Ls https://www.servercow.de/docker-compose/latest.php)/docker-compose-$(uname -s)-$(uname -m) > /usr/local/bin/docker-compose
chmod +x /usr/local/bin/docker-compose

Please use the latest Docker engine available and do not use the engine that ships with your distros repository.

2. Clone the master branch of the repository

git clone https://github.com/andryyy/mailcow-dockerized && cd mailcow-dockerized

3. Generate a configuration file. Use a FQDN (host.domain.tld) as hostname when asked.


4. Change configuration if you want or need to.

nano mailcow.conf

If you plan to use a reverse proxy, you can, for example, bind HTTPS to on port 8443 and HTTP to on port 8080.

You may need to stop an existing pre-installed MTA which blocks port 25/tcp. See this chapter to learn how to reconfigure Postfix to run besides mailcow after a successful installation.

5. Pull the images and run the composer file. The paramter -d will start mailcow: dockerized detached:

docker-compose pull
docker-compose up -d


You can now access https://${MAILCOW_HOSTNAME} with the default credentials admin + password moohoo.

The database will be initialized right after a connection to MySQL can be established.

Update mailcow

There is no update routine. You need to refresh your pulled repository clone and apply your local changes (if any). Actually there are many ways to merge local changes.

Step 1, method 1

Stash all local changes, pull changes from the remote master branch and apply your stash on top of it. You will most likely see warnings about non-commited changes; you can ignore them:

# Stash local changes
git stash
# Re-pull master
git pull
# Apply stash and remove it
git stash pop

Step 1, method 2

Fetch new data from GitHub, commit changes and merge remote repository:

# Get updates/changes
git fetch
# Add all changed files to local clone
git add -A
# Commit changes, ignore git complaining about username and mail address
git commit -m "Local config aat $(date)"
# Merge changes
git merge

If git complains about conflicts, solve them! Example:

CONFLICT (content): Merge conflict in data/web/index.php

Open data/web/index.php, solve the conflict, close the file and run git add -A + git commit -m "Solved conflict".

Step 1, method 3

Thanks to fabreg @ GitHub!

In case both methods do not work (for many reason like you're unable to fix the CONFLICTS or any other reasons) you can simply start all over again.

Keep in mind that all local changes to configuration files will be lost. However, your volumes will not be removed.

  • Copy mailcow.conf somewhere outside the mailcow-dockerized directory
  • Stop and remove mailcow containers: docker-compose down
  • Delete the directory or rename it
  • Clone the remote repository again (git clone https://github.com/andryyy/mailcow-dockerized && cd mailcow-dockerized). Pay attention to this step - the folder must have the same name of the previous one!
  • Copy back your previous mailcow.conf into the mailcow-dockerizd folder

If you forgot to stop Docker before deleting the cloned directoy, you can use the following commands:

docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)

Step 2

Pull new images (if any) and recreate changed containers:

docker-compose pull
docker-compose up -d --remove-orphans

Step 3

Clean-up dangling (unused) images and volumes:

docker rmi -f $(docker images -f "dangling=true" -q)
docker volume rm $(docker volume ls -qf dangling=true)