Windows DNS Scavenging Interview Questions and Answers

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

Also Read: Windows DNS Server Interview Questions and Answers

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

Also Read: Windows Server Administrator Interview Questions and Answers

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

Ipconfig /registerdns

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

Also Read: Active Directory (AD) Real Time Interview Questions and Answers

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

Also Read: Windows Group Policy Interview Questions and Answers

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

Also Read: Active Directory real time issues and solutions

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

Also Read: Types of Roles performed by DNS Server

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