Microsoft 70-411 Exam – Q83

You have a DNS server named DNS1 that runs Windows Server 2012 R2.

On DNS1, you create a standard primary DNS zone named adatum.com. You need to change the frequency that secondary name servers will replicate the zone from DNS1.

Which type of DNS record should you modify?

A. Name server (NS)
B. Start of authority (SOA)
C. Host information (HINFO)
D. Service location (SRV)

Correct Answer: B

Explanation:

A stub zone is a copy of a zone that contains only the original zone’s start of authority (SOA) resource record, the name server (NS) resource records listing the authoritative servers for the zone, and the glue address (A) resource records that are needed to identify these authoritative servers.

A DNS server that is hosting a stub zone is configured with the IP address of the authoritative server from which it loads. DNS servers can use stub zones for both iterative and recursive queries. When a DNS server hosting a stub zone receives a recursive query for a computer name in the zone to which the stub zone refers, the DNS server uses the IP address to query the authoritative server, or, if the query is iterative, returns a referral to the DNS servers listed in the stub zone.

Stub zones are updated at regular intervals, determined by the refresh interval of the SOA resource record for the stub zone. When a DNS server loads a stub zone, it queries the zone’s primary servers for SOA resource records, NS resource records at the zone’s root, and glue address (A) resource records. The DNS server attempts to update its resource records at the end of the SOA resource record’s refresh interval. To update its records, the DNS server queries the primary servers for the resource records listed earlier.

You can use stub zones to ensure that the DNS server that is authoritative for a parent zone automatically receives updates about the DNS servers that are authoritative for a child zone. To do this, add the stub zone to the server that is hosting the parent zone. Stub zones can be either file-based or Active Directory–integrated. If you use Active Directory–integrated stub zones, you can configure them on one computer and let Active Directory replication propagate them to other DNS servers running on domain controllers.
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