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Difficulty: EasyTroubleshooting DNS and Name Resolution Services

A network administrator runs the following query on a client workstation to test hostname resolution:

> nslookup webserver.corp.local
Server: dns1.corp.local
Address: 10.0.0.10

*** dns1.corp.local can't find webserver.corp.local: Non-existent domain

The administrator verifies that the target server is powered on, fully functional, and reachable directly by its IP address. Which of the following is the most likely cause of this issue?

  1. The DNS server is missing a host (A) record for the domain name.Answer
  2. B
    The client workstation used UDP port 53 for the query instead of TCP port 53.
  3. C
    The DNS server failed to map the IPv4 address because an AAAA record was requested.
  4. D
    The nslookup utility misinterpreted a non-authoritative server answer as a server failure.

Answer

The DNS server is missing a host (A) record for the domain name.
The 'Non-existent domain' (NXDOMAIN) error returned by nslookup indicates that the client successfully communicated with the DNS server, but the server does not have a matching Host (A) record configured in its DNS zone for the requested hostname.

Step-by-Step Solution

1
Analyze the nslookup command output.
The local DNS server at 10.0.0.10 responded with 'Non-existent domain' (NXDOMAIN).
This confirms network connectivity to the DNS server is working properly.
2
Evaluate the cause of the NXDOMAIN response.
NXDOMAIN means the queried name server has no record matching the requested hostname in its database.
Since the destination server is online and reachable via IP address, the failure is strictly due to the absence of the corresponding Host (A) resource record on the DNS server.

Key Concept

DNS Record Verification and NXDOMAIN Troubleshooting
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Topics

Troubleshooting DNS and Name Resolution Services

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