Goal: Generate IPv6 PTR records on the fly.

Additional benefit: Works with known hosts.

0.0.0.b.0.0.3.0.8.b.d.0.1.0.0.2.ip6.arpa {
    autoipv6ptr {
        suffix lan.mydomain.tld
    }
    file your.reverse.zone
    log
}

1.0.0.b.0.0.3.0.8.b.d.0.1.0.0.2.ip6.arpa {
    autoipv6ptr {
        suffix servers.mydomain.tld
        ttl 60
    }
    secondary {
        transfer from your.master.dns
    }
    log
}

It's necessary that file or secondary comes right after autoipv6ptr! This plugin always calls the next plugin and checks its return. It will only generate a PTR if a negative result comes back.

Using the docker infrastructure it's easy for you to build a working binary with the plugin:

docker build --pull --no-cache --output type=local,dest=result -f Dockerfile.build .

If everything checks out you'll find an x86_64 binary locally under result/coredns.

Run:

./result/coredns -conf tests/Corefile -p 1337

Test with dig. Known record:

dig @::1 -p 1337 +short -x 2001:db8:300::10
success.example.com.

Unknown record:

dig @::1 -p 1337 +short -x 2001:db8:300::11
20010db8030000000000000000000011.example.com.