In message <5274DEF9.3040405@necom830.hpcl.titech.ac.jp>, Masataka Ohta writes:
Mark Andrews wrote:
Over the cable modem?
Yes.
OK.
The cable modem is the CPE, which accept the DHCP packet to it.
A cable modem both accepts DHCP packets (for management of the modem) and passes DHCP packets through to the customer device.
Even if the CPE does so, which means there is no NAT, the key to update rDNS must, naturally, be contained only in DHCP reply to the CPE.
A cable modem is a media converter. That can be managed and that management interface also uses DHCP is irrelevent.
And, I'm afraid your draft assumes that the CPE behaves as a DHCP server for local hosts, which means the CPE is responsible for rDNS registration.
My draft assumes the CPE device is a PD client. It may or may not be a DHCP server for the internal network. Again that is irrelevent.
Masataka Ohta
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org