Using an external DNS service
If you want or have to use an external DNS service, you can either set a forwarder in Unbound or copy an override file to define external DNS servers:
!!! warning Please do not use a public resolver like we did in the example above. Many - if not all - blacklist lookups will fail with public resolvers, because blacklist server has limits on how much requests can be done from one IP and public resolvers usually reach this limits. Important: Only DNSSEC validating DNS services will work.
Method A, Unbound¶
Edit data/conf/unbound/unbound.conf and append the following parameters:
forward-zone:
name: "."
forward-addr: 8.8.8.8 # DO NOT USE PUBLIC DNS SERVERS - JUST AN EXAMPLE
forward-addr: 8.8.4.4 # DO NOT USE PUBLIC DNS SERVERS - JUST AN EXAMPLE
Restart Unbound:
docker-compose restart unbound-mailcow
Method B, Override file¶
cd /opt/mailcow-dockerized
cp helper-scripts/docker-compose.override.yml.d/EXTERNAL_DNS/docker-compose.override.yml .
Edit docker-compose.override.yml and adjust the IP.
Run docker-compose down ; docker-compose up -d.