mailcow/docs/first_steps.md

SSL (and: How to use Let's Encrypt)

mailcow dockerized comes with a snakeoil CA "mailcow" and a server certificate in data/assets/ssl. Please use your own trusted certificates.

mailcow uses 3 domain names that should be covered by your new certificate:

• ${MAILCOW_HOSTNAME}
• autodiscover.example.org
• autoconfig.example.org

Obtain multi-SAN certificate by 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 in mailcow.conf or setup a reverse proxy to enable connections to port 80. If you changed HTTP_BIND, then restart Nginx:

docker-compose restart nginx-mailcow

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

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.

Rspamd Web UI

At first you may want to setup Rspamds web interface which provides some useful features and information.

1. Generate a Rspamd controller password hash:

docker-compose exec rspamd-mailcow rspamadm pw

2. Replace the default hash in data/conf/rspamd/override.d/worker-controller.inc by your newly generated:

enable_password = "myhash";

3. Restart rspamd:

docker-compose restart rspamd-mailcow

Open https://${MAILCOW_HOSTNAME}/rspamd in a browser and login!

Optional: Reverse proxy

You don't need to change the Nginx site that comes with mailcow: dockerized. mailcow: dockerized trusts the default gateway IP 172.22.1.1 as proxy. This is very important to control access to Rspamd's web UI.

1. Make sure you change HTTP_BIND and HTTPS_BIND in mailcow.conf to a local address and set the ports accordingly, for example:

HTTP_BIND=127.0.0.1
HTTP_PORT=8080
HTTPS_PORT=127.0.0.1
HTTPS_PORT=8443

Recreate affected containers by running docker-compose up -d.

2. Configure your local webserver as reverse proxy:

Apache 2.4

<VirtualHost *:443>
    ServerName mail.example.org
    ServerAlias autodiscover.example.org
    ServerAlias autoconfig.example.org

    [...]
    # You should proxy to a plain HTTP session to offload SSL processing
    ProxyPass / http://127.0.0.1:8080
    ProxyPassReverse / http://127.0.0.1:8080
    ProxyPreserveHost On
    your-ssl-configuration-here
    [...]

    # If you plan to proxy to a HTTPS host:
    #SSLProxyEngine On
    
    # If you plan to proxy to an untrusted HTTPS host:
    #SSLProxyVerify none
    #SSLProxyCheckPeerCN off
    #SSLProxyCheckPeerName off
    #SSLProxyCheckPeerExpire off
</VirtualHost>

Nginx

server {
    listen 443;
    server_name mail.example.org autodiscover.example.org autoconfig.example.org;

    [...]
    your-ssl-configuration-here
    location / {
        proxy_pass http://127.0.0.1:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
    [...]
}