Which protocol is used to resolve hostnames to IP addresses on the Internet?

• A. DHCP
• B. FTP
• C. ARP
• D. DNS

Answer: (D)

DNS translates human-friendly hostnames into the numeric IP addresses used by computers on the Internet. When you type a web address, your device asks a DNS resolver to find the corresponding IP. The resolver may query a chain that starts at the root servers, moves to the appropriate top-level domain servers, and finally reaches the domain’s authoritative server to obtain the IP, with results cached to speed future lookups. This system makes it possible to reach sites by name rather than remembering numeric addresses, and its hierarchical design plus caching keeps lookups scalable and efficient.

Other options don’t fit because DHCP assigns IP addresses and other network configuration to hosts, not domain name mappings; ARP resolves IP addresses to MAC addresses on a local network, not Internet-wide hostnames to IPs; and FTP is a file transfer protocol, not a name-to-address resolution service.