It might be easier to drop your scope lease time really low, then delete all the dynamic DNS records and let them get re-created.
If you're waiting on DNS scavenging, there's no fast way to do it.
Error 31, DNS Update Failed – Seen this one before? The place to look for logs is: C:\Windows\System32\dhcp, check yours out and see if you have any error 31’s.
Even if you think things are good, it doesn’t necessarily mean that everything is working as well as it should.
You might be able to do this by tweaking some group policy settings, or by running a script to bulk "ipconfig /registerdns" on a bunch of clients.
Also ensure that reverse lookups are in place, and that permissions are correct on these too.Changing the timeouts is only going to help clients the next time they check in, which is usually after half the existing lease time, or sometimes during boot.You can approach this by manually forcing the clients to check in.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. 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.To configure DHCP Option 081, you must look at the DHCP server properties, under the DNS Tab in DHCP properties. After configuring the above provedure, the credentials and Dns Update Proxy group configuratuion will not update current or delete duplicate records. DHCP will give that duplicate named client an IP, but it will not register it into DNS.In case your DHCP server is a standalone Windows Server 2012 server, you can use the local administrator account credentials to log on while making the above configurations in the DHCP server.