Dhcp not updating in dns

This is because DHCP doesn’t own the record, the client does, even though DHCP registered it.

The way to get around this is you can configure DHCP’s Option 081 to update the record for all client, no matter if the client asks or not.

Therefore, even if they were to scavenge these records, assuming the time stamp has ever been reached, the machines will refresh themselves anyway!

By default, statically configured clients and remote access clients that do not rely on the DHCP server for DNS registration, will re-register their A & PTR records dynamically and periodically every 24 hours.

This applies to Windows 2000 Professional and all newer operating systems.

For domain controllers, due to the importance of keeping up to date and accurate SRV and other records, the Netlogon service will attempt to update these records every 60 minutes.

=============================================================== When a client shuts down, and later returns past the lease time, it may get a different IP address.

With the default settings, a duplicate A record gets registered by DHCP with the client’s new IP.

dhcp not updating in dns-59dhcp not updating in dns-52dhcp not updating in dns-15

Well, I will also offer the nitty gritty below the summary for those who want to read. But DHCP will register its PTR (reverse entry) record.

To configure DHCP Option 081, you must look at the DHCP server properties, under the DNS Tab in DHCP properties. If you have Windows 2008 R2 or Windows 2012 R2, in addition to configuring the DNS tab to force registration, you still must configure credentials and add the server to the Dns Update Proxy group.

Despite it being a DHCP Option, it’s not found in a DHCP server, scope or class option. After configuring the above provedure, the credentials and Dns Update Proxy group configuratuion will not update current or delete duplicate records. If DHCP is on a Windows 2008 R2 DC, to protect the DC when using the Dns Update Proxy group, you must secure the group by running: dnscmd /config /Open Acl On Proxy Updates 0 Using “DHCP Name Protection.” will register A and PTR record on behalf of a client, and will prevent a workstation (non-Windows) Name Squatting, meaning using a name that another machine (non-Windows or Windows) client that DHCP already registered , from registering it’s name.

You can use the following registry subkey to modify the TTL value: HKEY_LOCAL_MACHINE\SYSTEM\Current Control Set\Services\Tcpip\Parameters\Default Registration TTL . Scavenging Refresh and No Refresh settings must be equal to or less than the lease period.

For example, using the default DHCP lease period of 8 days with a 7day scavenge setting, is perfect.

Leave a Reply