This project presents a small Prosody server that allows anonymous logins and serves DNS-over-XMPP service.
docker run --rm -it -p 5222:5222 -v $PWD/config:/etc/prosody -v $PWD/certs:/certs -v $PWD/modules:/custom-modules prosody/prosody
Note that this project as it is is not ready for production. Most notably TLS certificates are self-signed and Prosody configuration allows running as root.