RBLDNSD

rbldnsd is a simple DNS server that allows to serve realtime blacklists (or whitelists) via DNS. All you need is a DNS zone file as described in the rbldnsd documentation. Then run the container with the zonename:type:fname,fname,fname... as the command and let the NS entry of your DNS zone point to the docker host.

Example usage via docker

docker run -it --rm \
    -v /path_to_your_zone_directory/:/var/lib/rbldnsd/:ro \
    -p 53:53/udp \
    kurthuwig/rbldnsd:latest \
    my-blacklist.example.com:ip4set:my-blacklist

Example usage via fig

This is an example fig file to launch rbldnsd. You only have to change the command and maybe the source directory for the volume containing the zone files.

rbldnsd:
  image: kurthuwig/rbldnsd:latest
  volumes:
   - /path_to_your_zone_directory/:/var/lib/rbldnsd/:ro
  ports:
   - "53:53/udp"
  command: "my-blacklist.example.com:ip4set:my-blacklist"

Testing

Normal DNS blacklists list an entry for 127.0.0.2 for testing purposes. If you did this as well, you can test your setup on a unix system with the host command:

$ host 2.0.0.127.my-blacklist.example.com. localhost
Using domain server:
Name: localhost
Address: 127.0.0.1#53
Aliases: 

2.0.0.127.my-blacklist.example.com has address 127.0.0.2

and the negative test with

$ host 1.0.0.127.my-blacklist.example.com. localhost
    Using domain server:
Name: localhost
Address: 127.0.0.1#53
Aliases: 

Host 1.0.0.127.my-blacklist.example.com. not found: 3(NXDOMAIN)