Which protocol is primarily responsible for translating domain names into IP addresses?

The Domain Name System (DNS) is the fundamental protocol that translates human-readable domain names, like www.example.com, into machine-readable IP addresses, such as 192.0.2.1. This translation is crucial for the operation of the internet, as computers and other network devices communicate using IP addresses. When a user enters a domain name in a web browser, a DNS query is sent out to resolve the domain name into its corresponding IP address, allowing the browser to locate and access the desired resource.

The other options serve different purposes and are not involved in the translation of domain names. File Transfer Protocol (FTP) is used for transferring files between a client and server, Hypertext Transfer Protocol (HTTP) is the protocol used for transferring web pages on the internet, and Internet Control Message Protocol (ICMP) is used for sending error messages and operational information related to IP processing. None of these protocols perform the function of resolving domain names into IP addresses, which underscores why DNS is the correct and essential choice for this role.