Question 6

nslookup is the command to use for testing DNS resolution.

The technician should use the nslookup command to test DNS resolution, as it specifically queries DNS servers to obtain domain name or IP address mapping information.

A) arp

The arp command is used to view and manipulate the Address Resolution Protocol cache, which maps IP addresses to MAC addresses. It does not test or resolve domain names, making it irrelevant for diagnosing DNS issues.

B) tracert

The tracert command is used to trace the route packets take to reach a destination host. While it can help identify network path issues, it does not perform DNS resolution or directly test DNS functionality.

C) ping

The ping command tests connectivity to a specified IP address or hostname by sending ICMP echo requests. Although it can indirectly indicate DNS issues by failing to resolve a hostname, it does not provide detailed information on DNS resolution itself.

D) nslookup

The nslookup command is specifically designed for querying DNS servers to resolve domain names to IP addresses and vice versa. It provides detailed information about the DNS records and is the most appropriate tool for diagnosing DNS resolution problems.

Conclusion

Nslookup is the definitive choice for testing DNS resolution issues due to its direct functionality in querying DNS servers. Other options, while useful for network diagnostics, do not serve the purpose of resolving domain names, thus failing to address the technician's need effectively.