Mail Server Docker
A secure, minimal-configuration mail server in a docker container, including webmail.
This repository is tailored to small private servers, where you own some domain(s) and
want to receive the mail for and send mail from this domain. It consists of 4 separate docker containers:
dovecot: The SMTP and IMAP server. This container uses postfix as MTA and dovecot as IMAP server.
All incoming mail to your own domains is accepted. For outgoing mail, only authenticated (logged in with username and password)
clients can send messages via STARTTLS on port 587. It should work with all mail clients.
rainloop: An automatically configured webmail interface. Note that you have to login with your full mail adress,
email@example.com of just
john.doe. By default, this will bind to
There is a webmail admin interface available at
adminand default password
12345, so you probably want to change that before connecting this container to
the internet. Note that just knowing the admin password isnt enough for other people to read your mail, since the mail password
isn't stored within rainloop. Also note that the admin
password will reset to the default values every time you restart the container.
Rainloop is released under CC BY-NC-SA 3.0, so you are only allowed to use this container for non-commercial purposes. They do
sell commercial licenses, if required.
owncloud: This provides CalDAV and CardDAV functionality, together with tons and tons of other stuff like cloud storage,
collaborative editing, etc. You should be able to login using your mail address automatically.
By default, this container will bind to
All user data is by default mapped
/srv/owncloudon the host.
As above, the default admin account has username
12345, so make sure to change this before connecting the container to the internet.
It is also possible to install a webmail interface within owncloud, so in theory you don't need rainloop.
That said, restarting the container after configuration changes
can be a bit rough and might require manual intervention so if you just want webmail, rainloop is probably preferrable.
If you encounter problems, try deleting
/srv/owncloud/owncloud.dband restarting the container.
mailpile: An early-alpha but promising webmail interface. It is currently not built by default,
but you can play around with it if you like. By default, the web interface will bind to
mailbase: This image is just an implementation detail. It is a workaround to allow sharing of configuration files between multiple docker images and redeploys.
$ git clone firstname.lastname@example.org:htmlgraphic/dockermail.git && cd dockermail $ make $ make run (runs complete docker-compose file)
Build IMAP Server Image
Build a working IMAP Server instance using a
Makefile and a few terminal commands
$ git clone https://github.com/htmlgraphic/dockermail.git && cd dockermail $ make $ make build
Test Driven Development
CircleCI - Test the Dockerfile process, can the container be built the correctly? Verify the build process with a number of tests. Currently with this service no code can be tested on the running container. Data can be echo and available grepping the output via
docker logs | grep value
Using CircleCI review the
Shippable - Run tests on the actual built container. These tests ensure the scripts have been setup properly and the service can start with parameters defined. If any test(s) fail the system should be reviewed closer.
Using Shippable review the
shippable.yml file. This service will use a
circle.yml file configuration but for the unique features provided by Shippable it is best to use the deadicated
shippable.yml file. This service will fully test the creation of your container and can push the complete image to your private Docker repo if you desire.
1) Add needed domains
Any domains you want to receive mail for to the file
2) Add user aliases
Edit the file
mailbase/aliases, to add any needed aliases:
email@example.com firstname.lastname@example.org email@example.com firstname.lastname@example.org email@example.com firstname.lastname@example.org @example.net email@example.com
An IMAP mail account is created for each entry on the right hand side.
Every mail sent to one of the addresses in the left column will
be delivered to the corresponding account in the right column.
3) Add user passwords
Edit the file
mailbase/passwords with the following:
To get the hash values, you can either install dovecot locally or use lxc-attach to attach to the running
container and run
doveadm pw -s <scheme-name> inside.
4) Build ALL Containers:
You can build single targets, so if you dont want the webmail you can just run
make dovecot instead. The Makefile is
extremely simple, dont be afraid to look inside.
STOP, if you need a IMAP server setup
5) Run container and map ports 25 and 143 from the host to the container.
To store your mail outside the container, map
a directory on your host. (This is recommended, otherwise
you have to remember to backup your mail when you want to restart the container)
This is done automaticaly by
Again, you can make
run-rainloop to only start specific containers. Look
at the Makefile to see what this does exactly. Note that you have to stop old containers
manually before invoking make, as this currently cannot be done automatically.
If you want to use owncloud, enter the public url at which owncloud can be reached (e.g.
owncloud.example.org) into the file
Known issues / Todo / Wishlist
- Improve this guide
- HELO isn't set correctly, which can lead to problems with outgoing mail on some servers