infrastructure/ansible/roles/coredns_docker_proxy/files/Corefile

. {
    errors
    cancel

    # Only allow requests to `.docker` records
    view docker {
        expr name() endsWith '.docker.'
    }

    # Strip the `.docker` suffix
    rewrite name suffix .docker . answer auto

    # Forward requests to Docker's DNS server
    forward . 127.0.0.11
}

. {
    acl {
        block
    }
}