What is the role of a DNS resolver?

• A. It queries authority servers on behalf of clients to resolve domain names to IPs and caches results
• B. It hosts zone files for domains
• C. It routes packets on the network
• D. It manages VPN connections

Answer: (A)

The main idea tested here is how a DNS resolver helps turn a domain name into an IP address by asking the DNS system on behalf of clients and then caching the results. A resolver sits between a user’s device and the DNS hierarchy. When you try to reach a domain, the resolver performs a recursive lookup: it talks to root servers, then the appropriate top-level domain servers, and finally the authoritative servers for the domain until it learns the correct IP. Once it has the IP, it returns it to you and stores the answer in its cache so future lookups for the same name can be answered quickly without repeating the whole search. This caching speeds up access and reduces DNS traffic over time. The other activities mentioned aren’t the resolver’s job: hosting zone files is done by authoritative name servers that store DNS records, routing packets is the role of network routers, and managing VPN connections is handled by VPN gateways or software.