Comprehensive and Detailed Explanation From Cisco Certified Support Technician (CCST) Official Cert Guide
The nslookup (Name Server Lookup) command is a DNS diagnostic utility used to query Domain Name System servers and retrieve information associated with domain names and IP addresses.
Option C — Correct: The nslookup utility enables network technicians to investigate DNS resolution problems by submitting queries to configured or explicitly specified DNS servers. It is available in Windows and many Unix-like operating systems.
A technician can execute the following command:
nslookup example.com
This requests DNS information for the specified domain. By default, the utility typically returns the resolved IP address records and identifies the DNS server responding to the query.
Additional DNS record types can also be examined:
A: Maps a hostname to an IPv4 address.
AAAA: Maps a hostname to an IPv6 address.
MX: Identifies mail exchange servers.
CNAME: Identifies a canonical-name alias.
Why the remaining options are incorrect:
A. ping: Primarily tests IP reachability using ICMP echo requests. It may perform hostname resolution but is not a general-purpose DNS record query utility.
B. traceroute: Identifies network hops along the path toward a destination.
D. netstat: Displays network connections, listening sockets, and network statistics.
Cisco identifies nslookup as a fundamental command for verifying DNS operations and troubleshooting name-resolution issues.
[References:, Cisco Certified Support Technician (CCST) IT Support 100-140 Official Cert Guide, Chapter 3: Networking and Network Connectivity, DNS (page 88) and nslookup (pages 94–95)., Cisco CCST IT Support Exam Topics, Domain 3.3: Examine Basic End-Device Connectivity to the Network., Cisco CCST IT Support Pearson Cert Prep, Lesson 15.10: nslookup Command., , ]
Submit