What is the role of the DNS resolver in the lookup process?

• A. To resolve the domain name into an IP address for the web browser.
• B. To assign IP addresses to new hosts.
• C. To host the DNS zone data.
• D. To block malicious domains.

Answer: (A)

DNS resolution translates a domain name into an IP address so a client can reach the destination. The DNS resolver performs that translation on behalf of the user’s device. It first checks its own cache for a recent answer; if not found, it performs recursive queries, starting with a root server, then querying the appropriate top-level domain servers, and finally contacting the authoritative servers for the domain to obtain the exact IP address. Once it gets the IP, the resolver returns it to the client so the browser can connect. The resolver may then cache the result for future requests until the TTL expires. This role is distinct from assigning IPs to hosts (that’s DHCP), hosting DNS zone data (that’s done by authoritative servers), or blocking domains (which is an extra security feature some resolvers provide).