On each DC/DNS server this NS will be the server itself, as each DC/DNS server is authoritative for it's own copy of the AD integrated DNS zones. Before you enable scavenging on the domain zones, you need to ensure that scavenging is disabled on DNS servers.
When scavenging is disabled on the zone, the timestamps are not replicated.
When a client does so, it uses separate and additional queries based on referral answers from servers. In general, the DNS query process occurs in two parts: The following figure shows an overview of the complete DNS query process.
Think of a DNS query as a client asking a server a two-part question, such as “Do you have any A resource records for a computer named ‘hostname.example.’?” When the client receives an answer from the server, it reads and interprets the answered A RR, learning the IP address for the computer it asked for by name. A client can sometimes answer a query locally using cached information obtained from a previous query.After re-enabling scavenging on the zone, you need to allow time for all machines to update their records and have their timestamps replicated.After two or three weeks, you should be able re-enable scavenging at the server level.Another type of zone, a , provides mapping from IP addresses back to DNS domain names.
For more information about reverse lookup zones, see Providing Reverse Lookup. If other domains are added below the initial domain, these domains can either be part of the same zone or belong to another zone.
By default, computers that are statically configured for TCP/IP attempt to dynamically register host (A) resource records and pointer (PTR) resource records for IP addresses that are configured and used by their installed network connections.
By default, all computers register records based on their fully qualified domain name (FQDN).
When a DNS client needs to look up a name used in a program, it queries DNS servers to resolve the name.
Each query message the client sends contains three pieces of information, specifying a question for the server to answer: For example, the name specified could be the FQDN for a computer, such as “host-a.example.”, and the query type specified to look for an address (A) RR by that name.
The DNS server can use its own cache of resource record information to answer a query.