N10-009 Network Troubleshooting Practice Question
A user reports that they can access the company's intranet website by IP address but not by its hostname (intranet.company.local). A technician checks the DNS server and finds that the A record exists and returns the correct IP. However, the user's browser still cannot resolve the hostname. Which of the following is the most likely cause?
⚠ Common exam trap
CompTIA often tests the distinction between server-side DNS configuration and client-side caching; the trap here is that candidates see 'A record exists and returns correct IP' and assume the DNS is fully functional, overlooking the client's local cache as the source of the problem.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The DNS cache on the user's workstation is corrupt.
The user can access the intranet by IP but not by hostname, which indicates that name resolution is failing. Since the DNS server has the correct A record, the issue is likely on the client side. A corrupt DNS cache on the workstation can cause the browser to use stale or invalid cached data, preventing successful resolution even though the authoritative DNS server returns the correct IP. Flushing the DNS cache with `ipconfig /flushdns` would resolve this.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The DNS cache on the user's workstation is corrupt.
Why this is correct
A corrupt DNS cache on the user's workstation stores incorrect or outdated hostname-to-IP address mappings. When the user attempts to access the intranet by its hostname, the local system consults this faulty cache first, leading to a resolution failure. However, direct access via the IP address bypasses the entire name resolution process, allowing the connection to succeed without relying on the compromised cache. This specific symptom strongly points to a local DNS resolution issue.
- ✗
The web server's certificate is expired.
Why it's wrong here
An expired SSL/TLS certificate on a web server primarily triggers security warnings in the user's web browser, indicating a potential trust or security risk. This issue affects the secure communication layer (HTTPS) after the hostname has already been successfully resolved to an IP address. It would not prevent the initial DNS lookup from succeeding, nor would it selectively block access by hostname while allowing direct IP connections. The user would still resolve the hostname but encounter a certificate error during the connection establishment.
When this WOULD be correct
This option would be correct in a scenario where a user reports being unable to access a secure website (HTTPS) and receives a certificate error, while other users can access the same site without issues, and the certificate is confirmed expired.
- ✗
The default gateway is misconfigured.
Why it's wrong here
A misconfigured default gateway would prevent the user's workstation from routing any network traffic to destinations outside its immediate local subnet. If the intranet website resides on a different subnet, accessing it by its IP address would fail entirely because the packets could not leave the local network. Since the user can successfully access the intranet by IP, the default gateway must be correctly configured and functioning for external subnet communication.
- ✗
The file server is overloaded.
Why it's wrong here
An overloaded server, whether a file server or a web server, would exhibit slow response times or connection timeouts for all incoming requests, regardless of how the destination was specified. The issue would manifest as a general inability to connect or extremely poor performance, affecting both IP address and hostname access equally. It would not selectively prevent hostname resolution while permitting direct IP connections, as server load occurs after name resolution.
When this WOULD be correct
A user reports slow access to shared files on a file server, and other users experience similar issues. The technician finds high CPU and disk usage on the file server. In that scenario, an overloaded file server would be the likely cause.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓The DNS cache on the user's workstation is corrupt.Correct answer▾
Why this is correct
A corrupt DNS cache on the user's workstation stores incorrect or outdated hostname-to-IP address mappings. When the user attempts to access the intranet by its hostname, the local system consults this faulty cache first, leading to a resolution failure. However, direct access via the IP address bypasses the entire name resolution process, allowing the connection to succeed without relying on the compromised cache. This specific symptom strongly points to a local DNS resolution issue.
✗The web server's certificate is expired.Wrong answer — click to see why▾
Why this is wrong here
An expired web server certificate would cause browser security warnings but would not prevent hostname resolution; the user can access by IP, indicating DNS resolution is working, but the browser fails to resolve the hostname, pointing to a client-side DNS caching issue.
★ When this WOULD be the correct answer
This option would be correct in a scenario where a user reports being unable to access a secure website (HTTPS) and receives a certificate error, while other users can access the same site without issues, and the certificate is confirmed expired.
Why candidates choose this
Candidates may confuse certificate errors with name resolution failures, assuming that an expired certificate blocks all access, or they may think the browser's inability to load the site is due to a security certificate issue rather than DNS.
✗The file server is overloaded.Wrong answer — click to see why▾
Why this is wrong here
An overloaded file server would not prevent DNS resolution of a hostname; the user can access the intranet via IP, indicating network connectivity and web server functionality are intact.
★ When this WOULD be the correct answer
A user reports slow access to shared files on a file server, and other users experience similar issues. The technician finds high CPU and disk usage on the file server. In that scenario, an overloaded file server would be the likely cause.
Why candidates choose this
Candidates may confuse file server and web server roles, or assume any server overload could cause name resolution failures, overlooking that DNS is a separate service.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Quick reference
Common DNS Record Types
| Record | Purpose | Example |
|---|---|---|
| A | IPv4 address mapping | example.com → 93.184.216.34 |
| AAAA | IPv6 address mapping | example.com → 2606:2800::1 |
| CNAME | Alias to another hostname | www → example.com |
| MX | Mail server for domain | example.com → mail.example.com (priority 10) |
| TXT | Text data (SPF, DKIM, verification) | v=spf1 include:_spf.example.com ~all |
| NS | Authoritative name servers | example.com NS ns1.example.com |
| PTR | Reverse DNS (IP → hostname) | 34.216.184.93.in-addr.arpa → example.com |
| SOA | Zone authority record | Primary NS, admin email, serial, TTL defaults |
Go deeper
Related to this question
Learn chapter
IP Address Conflict Resolution
Key term
Fully Qualified Domain Name
A Fully Qualified Domain Name is the complete and unambiguous website or server name that includes the host, domain, and top-level domain, leaving no room for guesswork.
Key term
CAN
A CAN (Controller Area Network) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer.
About these practice questions
Courseiva writes every N10-009 question from scratch — 464 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This N10-009 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the N10-009 exam.