The answer is to use nslookup google.com and traceroute 8.8.8.8. When a server can ping its gateway and internal hosts but cannot reach external websites, the problem is isolated to either DNS resolution or routing beyond the local network. The nslookup command tests whether the configured DNS server can translate a domain name like google.com into an IP address, directly checking for a DNS failure. Meanwhile, traceroute to an external IP such as 8.8.8.8 bypasses DNS entirely, revealing where packets are dropped or misrouted after the gateway. On the CompTIA Linux+ XK0-005 exam, this scenario tests your ability to distinguish between Layer 3 connectivity and name resolution issues—a common trap is assuming a ping failure means a total network outage, but here the gateway is reachable. Remember the mnemonic: “Ping the gate, then DNS and trace—if websites fail, check that space.”
XK0-005 Troubleshooting Practice Question
This XK0-005 practice question tests your understanding of troubleshooting. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A system administrator is troubleshooting a network issue where a server cannot reach external websites. The server can ping the default gateway and internal hosts. Which TWO commands should the administrator use to further diagnose the problem? (Choose TWO.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
nslookup google.com
The server can reach internal hosts and the default gateway, which rules out Layer 2/3 connectivity issues within the local network. However, it cannot reach external websites, suggesting a DNS resolution failure or a routing problem beyond the gateway. 'nslookup google.com' (A) tests DNS resolution by querying the configured DNS server for the IP address of google.com; if it fails, the issue is with DNS. 'traceroute 8.8.8.8' (E) traces the path to a known external IP (Google's public DNS), bypassing DNS, to determine if packets are being dropped or misrouted after the gateway.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
nslookup google.com
Why this is correct
Tests DNS resolution; if it fails, that could be the reason for not reaching external sites by name.
Related concept
Read the scenario before looking for a memorised answer.
✗
route -n
Why it's wrong here
route -n shows routing table, but since internal connectivity works, routing is likely correct.
✗
ping 127.0.0.1
Why it's wrong here
ping loopback tests local stack, not external connectivity.
✗
ifconfig eth0
Why it's wrong here
ifconfig shows interface configuration, which appears fine since internal connectivity works.
✓
traceroute 8.8.8.8
Why this is correct
traceroute shows the path to an external IP, identifying where packets are lost.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose 'route -n' (B) thinking it will show a missing default route, but since the server can ping the gateway, the default route is present; the real issue is either DNS or a routing problem beyond the first hop, which 'traceroute' (E) specifically addresses.
Trap categories for this question
Command / output trap
route -n shows routing table, but since internal connectivity works, routing is likely correct.
Detailed technical explanation
How to think about this question
DNS resolution uses UDP port 53 by default; if 'nslookup' fails, the issue could be a misconfigured /etc/resolv.conf, a firewall blocking UDP 53, or the DNS server being unreachable. 'traceroute' sends packets with increasing TTL values (starting at 1) and listens for ICMP Time Exceeded messages from each hop; a sudden stop at the gateway or a series of asterisks after the gateway indicates a routing blackhole or a firewall dropping packets. In real-world scenarios, an administrator might also check the default gateway's routing table or use 'tcpdump' to see if DNS queries leave the server.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this XK0-005 question in full detail.
Troubleshooting — This question tests Troubleshooting — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: nslookup google.com — The server can reach internal hosts and the default gateway, which rules out Layer 2/3 connectivity issues within the local network. However, it cannot reach external websites, suggesting a DNS resolution failure or a routing problem beyond the gateway. 'nslookup google.com' (A) tests DNS resolution by querying the configured DNS server for the IP address of google.com; if it fails, the issue is with DNS. 'traceroute 8.8.8.8' (E) traces the path to a known external IP (Google's public DNS), bypassing DNS, to determine if packets are being dropped or misrouted after the gateway.
What should I do if I get this XK0-005 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This XK0-005 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 XK0-005 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.