220-1101 Question 39
Single answerTest connectivityA technician is troubleshooting a Windows laptop that cannot open any websites. The laptop shows it is connected to the office Wi-Fi, and other users on the same wireless network can browse normally. The technician wants to determine whether the issue is basic network connectivity, DNS resolution, or access beyond the local router. Which command should the technician run FIRST to most efficiently verify whether the laptop can reach the local gateway?
- A
ping 127.0.0.1
- B
ping 8.8.8.8
- C
ping
- D
nslookup www.example.com
Show answer and explanation
Correct answer: C
Explanation
A structured connectivity test should move from the nearest network point outward. In this scenario, the laptop is already connected to Wi-Fi, so the technician should first verify whether it can reach the default gateway. If pinging the default gateway fails, the issue is likely with local connectivity, IP addressing, WLAN association quality, or the router interface. If the gateway responds, the next logical step is to test an external IP address such as 8.8.8.8 to verify internet reachability without DNS. If that works, the technician should then test DNS with a command such as nslookup. This layered approach aligns with common troubleshooting best practices used in CompTIA A+ objectives and standard vendor documentation for TCP/IP troubleshooting in Windows environments.
- A. Incorrect.
This tests the TCP/IP stack on the local machine by sending traffic to the loopback address. It is useful if you suspect the NIC driver or TCP/IP stack is corrupted, but it does not verify connectivity to the wireless network or the local router. A candidate might choose this because it is a common first ping test, but it is not the most efficient next step when the laptop is already associated with Wi-Fi and the goal is to verify reachability to the gateway.
- B. Incorrect.
This tests whether the laptop can reach an external IP address on the internet without relying on DNS. It is helpful later to distinguish internet reachability from DNS problems. However, it skips an important troubleshooting step: confirming the device can even communicate with its local router first. If the gateway is unreachable, testing 8.8.8.8 adds unnecessary variables.
- C. Correct.
This is correct because pinging the default gateway verifies local Layer 3 connectivity between the laptop and the router or access point's routing interface. It is the most efficient first test when the user is connected to Wi-Fi but cannot browse. If the gateway does not respond, the issue is likely local network connectivity, incorrect IP configuration, wireless isolation, or a router-side problem rather than DNS.
- D. Incorrect.
This checks DNS name resolution by querying a DNS server for the IP address of a hostname. It is useful if the system can reach IP addresses but not websites by name. However, it does not first confirm whether the laptop can communicate with the local gateway, so it is not the best initial test for isolating the fault domain.