Examkin

Question

Difficulty: EasyTroubleshooting DNS and Name Resolution Services

A network technician executes the `nslookup server1.lab.local` command from a client workstation to verify hostname resolution. The command yields the following output:

Server: dns1.lab.local
Address: 10.0.0.2

*** dns1.lab.local can't find server1.lab.local: Non-existent domain

Which of the following issues is the most likely cause of this error message?

  1. The host record (A record) for server1.lab.local is missing from the DNS server database.Answer
  2. B
    The DNS server at 10.0.0.2 is unreachable or experiencing network downtime.
  3. C
    The workstation client failed to query over TCP port 53, which is required for all standard hostname queries.
  4. D
    The domain name requires a CNAME alias record because IPv4 hostnames cannot be mapped directly to IP addresses.

Answer

The host record (A record) for server1.lab.local is missing from the DNS server database.
The correct answer identifies that the DNS server responded with an NXDOMAIN (Non-existent domain) message, which confirms the DNS service is operational at 10.0.0.2 but lacks an active host (A) record for the requested hostname.

Step-by-Step Solution

1
Analyze the `nslookup` output lines.
The local workstation successfully contacted the DNS server named `dns1.lab.local` at IP address `10.0.0.2`.
Establishing that the server responded rules out network reachability or local service outage issues.
2
Interpret the specific error string `Non-existent domain` (NXDOMAIN).
Identified that the DNS server searched its records but found no mapping for `server1.lab.local`.
An NXDOMAIN response directly signifies that no corresponding resource record (such as an A or AAAA record) exists in the queried zone file.

Key Concept

Interpreting nslookup output and NXDOMAIN errors during name resolution troubleshooting
Rate this question

Topics

Troubleshooting DNS and Name Resolution Services

More questions from this topic