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Difficulty: EasyTroubleshooting DNS and Name Resolution Services

A system administrator executes a lookup command to test hostname resolution for a new database server. The command output is as follows:

text
$ dig db01.company.local
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 38419
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

Which of the following issues is directly indicated by the response status in this output?

  1. The queried domain name does not exist or lacks a matching resource record on the DNS server.Answer
  2. B
    UDP port 53 traffic is blocked by a network firewall between the client and the DNS server.
  3. C
    The DNS server is completely offline and unreachable by host devices.
  4. D
    The client is missing a reverse PTR record required for forward hostname lookup.

Answer

The NXDOMAIN status indicates that the specified domain name does not exist in the DNS database.
The NXDOMAIN (Non-Existent Domain) status code indicates that the targeted DNS server was reached successfully, but no valid host or A record exists for the queried domain name (db01.company.local).

Step-by-Step Solution

1
Examine the status field in the dig command output header.
The status field explicitly states `status: NXDOMAIN`.
The status field reports the response code returned by the DNS resolver.
2
Interpret the meaning of the NXDOMAIN response code.
NXDOMAIN stands for Non-Existent Domain.
This code confirms that the DNS server successfully received the query but holds no matching A or host record for the target name.

Key Concept

DNS Response Codes (NXDOMAIN)
Estimated Time:45s
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Topics

Troubleshooting DNS and Name Resolution Services

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