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Zorluk: OrtaDNS Lookup and Name Resolution Roles in Enterprise Networks

An enterprise client workstation sends a DNS name resolution request for an external web service to its local internal Active Directory DNS server. The internal DNS server is configured to perform recursion but does not hold an authoritative zone or a local cached entry for the requested domain name. Which action does the internal DNS server perform to resolve the query for the client workstation?

  1. It performs iterative queries against external root, top-level domain (TLD), and authoritative DNS servers on behalf of the workstation and returns the final resolution result to the client.Cevap
  2. B
    It instructs the client workstation to establish a TCP port 53 connection directly with external root DNS servers to complete the query.
  3. C
    It sends a DNS referral message back to the workstation containing the IP addresses of public root servers so the host can perform its own iterative lookups.
  4. D
    It converts the host's forward lookup request into a reverse PTR query before forwarding it directly to the target server's gateway.

Cevap

The internal DNS server performs iterative queries against root, TLD, and authoritative DNS servers on behalf of the workstation and returns the resolved address to the client.
In enterprise network operations, host workstations make recursive DNS queries to an assigned internal DNS server. When the internal DNS server does not possess the record in cache or local authoritative zones, it acts as a recursive resolver by sending a series of iterative queries to external root, TLD, and authoritative servers. Once the final IP address is retrieved, the internal DNS server sends the answer back to the client host.

Adım Adım Çözüm

1
Analyze client-to-DNS resolver request type
The client host sends a recursive query to its configured local internal DNS server, delegating the full lookup task to that server.
End-user hosts rely on internal recursive resolvers to handle multi-step domain hierarchy queries.
2
Evaluate internal DNS server cache and authority state
The server has no local zone authority or cached entry for the external domain.
Because it lacks local answers, the recursive server must query external hierarchy servers starting at the root level.
3
Trace external resolution mechanism
The internal DNS server performs iterative requests upstream (Root -> TLD -> Authoritative Server) until obtaining the final record, which it caches and sends back to the client workstation.
This insulates internal clients from direct internet exposure and centralizes enterprise DNS caching.

Anahtar Kavram

DNS Recursive Resolver vs Iterative Query Roles in Enterprise Name Resolution
Tahmini Süre:1m 15s
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DNS Lookup and Name Resolution Roles in Enterprise Networks

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