Once all prerequisites for enabling the use of scavenging are met, it can start for a server zone when the current server time is greater than the value of the start scavenging time for the zone.
The server sets the time value to start scavenging on a per-zone basis whenever one of the following events occurs:
Dynamic updates are enabled for the zone.
A change in the state of the Scavenge stale resource records check box is applied. You can use the DNS console to modify this setting at either an applicable DNS server or one of its primary zones.
The DNS server loads a primary zone enabled to use scavenging.
This can occur when the server computer is started or when the DNS Server service is started.
A zone resumes service after having been paused.
When the previous events occur, the DNS server sets the value of start scavenging time by calculating the following sum:
Current server time + Refresh interval = Start scavenging time
This value is used as a basis of comparison during scavenging operations.