Why Does Only One User Experience Incorrect DNS Resolution?

N10-009 By islever Editorial Last updated

Short answer

A Hosts file

Question

A user is unable to navigate to a website because the provided URL is not resolving to the correct IP address. Other users are able to navigate to the intended website without issue. Which of the following is most likely causing this issue?
  1. Hosts file Correct Answer
  2. Self-signed certificate
  3. Nameserver record
  4. IP helper

Key Takeaways

This question tests understanding of DNS resolution order and local versus global configuration issues, with the common trap being confusion between local overrides and broader DNS infrastructure failures.

When a single user cannot resolve a URL to the correct IP while others access it normally, the issue is typically local rather than network-wide. Community consensus confirms the hosts file is the most likely culprit due to its ability to override standard DNS resolution.

Common mistake: Users often select Nameserver record because they associate URL resolution failures with DNS server problems, but this would cause widespread resolution failures across all clients instead of isolating to one user.

Expert Analysis

Why the Answer Is Correct

The hosts file is a local, static text file that maps hostnames to IP addresses before any external DNS query is initiated. Because it resides directly on the endpoint, an incorrect or malicious entry will only impact that specific machine's resolution behavior. Modern operating systems evaluate the hosts file prior to contacting recursive DNS servers, making it a direct override mechanism. As highlighted by community contributors, this local precedence perfectly explains why other users experience no connectivity issues.

Why the Other Options Are Wrong

A self-signed certificate affects HTTPS trust and encryption validation, not IP address resolution. A nameserver record refers to authoritative DNS data; if misconfigured, it would disrupt resolution for every client querying that specific zone. An IP helper service forwards DHCP broadcast packets across routed subnets and plays no role in hostname-to-IP mapping or traffic routing.

Community Comment Notes

Multiple high-voted comments emphasize that the hosts file acts as a local DNS override, directly validating option A. One contributor notes its historical utility for blocking websites by redirecting domains locally, demonstrating its powerful precedence over live DNS queries. Another analyst stresses that isolated resolution failures strongly indicate a local configuration problem rather than a network-wide DNS outage. These practical insights reinforce the troubleshooting methodology of prioritizing endpoint checks when symptoms remain user-specific.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

Always isolate the scope of the problem during troubleshooting questions; if only one device or user is affected, prioritize local configurations over network infrastructure. Practice recognizing resolution order hierarchies, such as how the hosts file bypasses DNS, to quickly eliminate distractors on exam day.

Community Votes

A
100%

100% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 3 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 3

  1. chupapi_001 👍 4 Answered A
    The hosts file is a local system file that maps hostnames to IP addresses and can override normal DNS resolution . When only one user is experiencing resolution issues while others can access the website normally, this strongly suggests a local configuration problem rather than a network-wide DNS issue.
  2. HeatSquad77 👍 4 Answered A
    A. hosts file The predecessor to DNS, a static text file that resides on a computer and is used to resolve DNS hostnames to IP addresses. Automatically mapped to a host’s DNS resolver cache in modern systems. The hosts file has no extension.
  3. chrys 👍 2
    Hosts file is checked before DNS. It's actually a fun and simple way to hack a system. I had to use it once to keep users from using a PC running an XRAY controller to get on Facebook and other social media sites. Quick 'n' dirty ;-)

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