What is DNS Scavenging?
DNS Scavenging is to cleanup and removal of stale DNS records, like housekeeping activity to delete unwanted or unused DNS entries in DNS server/zone, it only cleanup the dynamic DNS record not the record created manually
What is Dynamic DNS record?
The record created dynamically by client/server on DNS zone, automatically added to zones when computers start on the network
How to force the DNS Dynamic Update?
Simple way is restart the system which trigger the DNS Dynamic Update, we can user the below command to force DNS Dynamic Update
You can also restart the netlogon service on service.msc
If DNS Dynamic updates not working what are the checks needs to do?
Check the primary DNS configuration on the system, Primary DNS server should be reachable from client in order to register DNS record
Register this connections addresses in DNS should be selected on network card properties (advance options where you configure the IP Address)
Also Check the DHCP configuration if the managed through DHCP
What are Prerequisites to do the DNS scavenging?
Scavenging must be enabled on DNS server and on the zone you want to scavenging
DNS records must be dynamically added to zones or you can manually modified the timestamp configuration
What is Scavenging Period?
Default value for Scavenging is seven days (the minimum allowed value for this is one hour)
scavenging time on DNS zone is the server to determine when a zone becomes available for scavenging
So 7 + 7, every 14 days
When the Record refreshes happen? (Dynamic updates of record)
Every DNS record time stamp been updated While the time of computer restart
A periodic refresh is sent by the computer every 24 hours
Network services make refresh attempts, like DHCP servers, which renew client address, cluster servers, which register and update records for a cluster, and the Net Logon service, which can register and update resource records that are used by AD domain controllers
So that the record not taken as a stale DNS record
What is Scavenging servers?
Is DNS Scavenging configured in all Domain Controllers?
Not all DNS servers are Scavenging servers, you can configure/promote DNS server to Scavenging servers
Zone parameter on advanced settings that enables you to specify a restricted list of IP addresses for DNS servers that are enabled to perform scavenging
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