I run BIND on the router at each site I administer. The router gets a real domain name and is the authoritative nameserver for that domain. isc-dhcp-server is

I run BIND on the router at each site I administer. The router gets a real domain name and is the authoritative nameserver for that domain. isc-dhcp-server is configured to assign a publicly routable IPv6 to each client, and update the BIND zone records with the client hostnames, so each client automatically has a publicly routable domain name, hostname.domain.com, with AAAA records pointing to their IPv6. They are firewalled of course.