2,4 KiB
!!! warning
mailcow dockerized comes with a snake-oil CA "mailcow" and a server certificate in data/assets/ssl. Please use your own trusted certificates.
mailcow uses at least 3 domain names that should be covered by your new certificate:
- ${MAILCOW_HOSTNAME}
- autodiscover.example.org
- autoconfig.example.org
Let's Encrypt
This is just an example of how to obtain certificates with certbot. There are several methods!
1. Get the certbot client:
wget https://dl.eff.org/certbot-auto -O /usr/local/sbin/certbot && chmod +x /usr/local/sbin/certbot
2. Make sure you set HTTP_BIND=0.0.0.0 and HTTP_PORT=80 in mailcow.conf or setup a reverse proxy to enable connections to port 80. If you changed HTTP_BIND, then rebuild Nginx:
docker-compose up -d
3. Request the certificate with the webroot method:
cd /path/to/git/clone/mailcow-dockerized
source mailcow.conf
certbot certonly \
--webroot \
-w ${PWD}/data/web \
-d ${MAILCOW_HOSTNAME} \
-d autodiscover.example.org \
-d autoconfig.example.org \
--email you@example.org \
--agree-tos
!!! warning Remember to replace the example.org domain with your own domain, this command will not work if you don't.
4. Create hard links to the full path of the new certificates. Assuming you are still in the mailcow root folder:
mv data/assets/ssl/cert.{pem,pem.backup}
mv data/assets/ssl/key.{pem,pem.backup}
ln $(readlink -f /etc/letsencrypt/live/${MAILCOW_HOSTNAME}/fullchain.pem) data/assets/ssl/cert.pem
ln $(readlink -f /etc/letsencrypt/live/${MAILCOW_HOSTNAME}/privkey.pem) data/assets/ssl/key.pem
5. Restart affected containers:
docker-compose restart postfix-mailcow dovecot-mailcow nginx-mailcow
When renewing certificates, run the last two steps (link + restart) as post-hook in a script.
Check your configuration
To check if nginx serves the correct certificate, simply use a browser of your choice and check the displayed certificate.
To check the certificate served by dovecot or postfix we will use openssl:
# Connect via SMTP (25)
openssl s_client -starttls smtp -crlf -connect mx.mailcow.email:25
# Connect via SMTPS (465)
openssl s_client -showcerts -connect mx.mailcow.email:465
# Connect via SUBMISSION (587)
openssl s_client -starttls smtp -crlf -connect mx.mailcow.email:587