What is the purpose of the Nslookup tool?

The Nslookup tool is primarily used to resolve domain names into IP addresses and vice versa. It is an essential utility for network troubleshooting and management, allowing users to query DNS (Domain Name System) servers to obtain domain name or IP address mapping information. This functionality helps in diagnosing issues related to domain resolution, ensuring that domain names are correctly pointing to their associated IP addresses. By enabling users to check DNS information and configurations, Nslookup is crucial for verifying the correctness and responsiveness of domain registrations and DNS services.

The other options pertain to different functionalities that do not align with the primary purpose of Nslookup. Testing internet speed, displaying active connections, and monitoring network activity involve distinct tools and methods unrelated to the DNS resolution capability of Nslookup.