220-1102 Question 107
Single answernslookupA technician is troubleshooting a user's report that the company intranet site, intranet.corp.local, will not open from a Windows workstation. The user can reach internet sites by IP address and by name, but the intranet site fails with a browser message indicating the server cannot be found. The technician suspects a DNS issue specific to the internal host record. Which command should the technician run first to verify whether the workstation can resolve the intranet server name using DNS?
- A
nslookup intranet.corp.local
- B
ping 127.0.0.1
- C
ipconfig /release
- D
netstat -an
Show answer and explanation
Correct answer: A
Explanation
This scenario is a classic name resolution troubleshooting case. Because the user can access other sites and the failure is limited to a specific internal hostname, the technician should first verify DNS resolution for that host. The nslookup utility is designed for this purpose: it queries DNS servers and returns the IP address associated with the hostname, or an error if resolution fails. This helps distinguish DNS problems from routing, browser, or web server issues. As a best practice in network troubleshooting, technicians should test the most likely point of failure with the least disruptive command first. Microsoft documentation and standard DNS troubleshooting practices identify nslookup as an appropriate tool for validating hostname-to-IP resolution from a client system.
- A. Correct.
Correct. The nslookup command is used to query DNS and verify whether a hostname resolves to an IP address. Running "nslookup intranet.corp.local" directly tests the suspected problem: whether the workstation can resolve the internal server name through DNS. This is the most appropriate first step when the symptom points to name resolution failure for a specific host.
- B. Incorrect.
Incorrect. Pinging 127.0.0.1 tests the local TCP/IP stack on the workstation, not DNS resolution for a remote host. It is useful when checking whether networking components are functioning locally, but it does not help determine whether intranet.corp.local has a valid DNS record or whether the workstation's DNS server can resolve it.
- C. Incorrect.
Incorrect. "ipconfig /release" drops the current DHCP-assigned IP configuration. This is not a diagnostic command for checking whether a hostname resolves in DNS, and using it first could unnecessarily disrupt the user's network connectivity. A technician would typically gather more evidence before resetting addressing information.
- D. Incorrect.
Incorrect. "netstat -an" displays active connections and listening ports. It can help identify whether applications are communicating over the network, but it does not query DNS records or confirm whether a specific hostname resolves to an IP address.