Realising this is an old thread but thought I'd share this. In a nutshell: "Clients with dynamically-set network connections (DHCP clients) will communicate with both the authoritative DNS server and the DHCP server for updating A and PTR records. The DHCP client will communicate with the authoritative DNS server directly for updating its A record, but the DHCP server updates the DNS server with the client’s PTR record on behalf of the DHCP client." ... View more