There is a small script that updates the reverse record for a given ip address.
It can be called on the VPN VM as
/home/jim/scripts/dns/./dyn-reverse-dns.sh <ipv4 ou ipv6> <nom de domaine à y assigner> <serveur DNS à updater>
For the moment, the DNS server is 172.16.42.2 (I just set up this argument for more modularity in the future).
/home/jim/scripts/dns/./dyn-reverse-dns.sh 184.108.40.206 brique.e-jim.be 172.16.42.2
It can have those different return codes:
Most of the time, more info can be found in the stdout.
I hope this can help someone implement reverse DNS into ISPng (including the needed verification that the user has administrative rights on the IP).