This is a small Docker container that can be used as a caching, forwarding-only domain name server for Docker hosts.
To build the docker container:
$ docker build -t unbound-forwarder:latest .
When running the container, you need to pass an IP address to which queries should be forwarded to:
$ export FORWARDER_IP=10.0.0.1
$ docker run -p 53:53/udp -e FORWARDER_IP=$FORWARDER_IP unbound-forwarder:latest