Dhcp is not dynamically updating dns
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.
If you lower the lease, you need to lower the scavenge settings.The default Time To Live (TTL) value used for dynamic registrations is 20 minutes.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.It will scavenge updated records that have reached their time stamp. Static records will not get scavenged, since they have a 0 time stamp.However, if you run dnscmd /Age All Records, it will timestamp all records, making them eligible for scavenging. When viewing a static record, it will show as the following: However, regarding static records, if you use force age all records using the dnscmd /Age All Records.
If the “Delete the record when it becomes stale” box was checked at time of the record creating, it will set a Time Stamp on it, which will make it eligible for scavenging. Rough formula to go by: No Refresh Refresh * 2 the point in time during the 3 day scavenge period.