Which protocol translates domain names into IP addresses?

The correct answer is DNS, which stands for Domain Name System. This protocol is essential for the functionality of the internet as it provides a way to translate human-friendly domain names (like www.example.com) into IP addresses (such as 192.0.2.1) that computers use to identify each other on the network.

When a user enters a domain name in their web browser, the DNS lookup process occurs, routing the request to the appropriate DNS server which then retrieves the corresponding IP address. This translation is vital because, while humans find domain names easy to remember, computers and networking equipment work with numerical IP addresses for communication across networks.

The other protocols listed do not serve this purpose. HTTP (Hypertext Transfer Protocol) is used for transferring web pages, FTP (File Transfer Protocol) focuses on transferring files between systems, and IPX (Internetwork Packet Exchange) was used in the past for network communication in Novell networks but does not deal with DNS functions. Hence, DNS is the definitive protocol for translating domain names into IP addresses.