DHCP not registering DNS names

[Guest]

I have DHCP and DNS running on a domain controller. For some workstations
DNS entries are not getting updated in the forward lookup zone. All entries
are being updated in the reverse lookup zone. On the DHCP server under the
DNS tab in properties I have the following checked:
Enable DNS dynamic updates according to the settings below:
Always dynamically update DNS A and PTR records
Discard A and PTR records when a lease is deleted
Dynamically update DNS A and PTR records for DHCP clients that do not
request update (...)

DNS is active directory integrated allowing secure updates only.

 

[Achint Setia {MSFT}]

When you enable the DHCP server to do both A and PTR registrations on behalf
of the clients, the client has no control over dynamic DNS updation as the
server takes that responsibility.
Its rather strange that a few clients aren't having their A records updated.
Ok, do the following test and see if the clients are able to do these
updates themselves or the problem lies elsewhere.

Check the "Dynamically Update A and PTR records only if requested by the
clients" on the server.
Also, on the problematic clients set the "Register this connection's address
in DNS". (in the TCP/IP Properties->Advanced tab->DNS)

See if the registration takes place this time.