You are troubleshooting a network issue where users are unable to access websites using domain names but can access them using IP addresses. Which function of DNS is most relevant to resolving this issue?

The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, or other resources connected to the Internet or a private network. Its primary function is to translate human-readable domain names (e.g., www.example.com) into the numerical IP addresses (e.g., 93.184.216.34) needed for locating and identifying computer services and devices. The scenario describes a classic DNS failure: name resolution is not working, but direct IP-based communication is successful. Therefore, the domain-to-IP address resolution function of DNS is the most relevant aspect to investigate and resolve the issue.

A. The Dynamic Host Configuration Protocol (DHCP), not DNS, is responsible for dynamically assigning IP addresses to devices on a network.
B. Encryption for web traffic is managed by protocols like Transport Layer Security (TLS), often implemented as HTTPS, not by the core DNS resolution function.
D. The Address Resolution Protocol (ARP) is used on a local network to convert IP addresses to physical MAC addresses, a different function from DNS.

1. Kurose, J. F., & Ross, K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson. In Chapter 2, Section 2.5, "The Domain Name System," the text states, "The main function of the DNS is to translate hostnames to IP addresses."

2. Mockapetris, P. (1987). RFC 1034: Domain Names - Concepts and Facilities. Internet Engineering Task Force (IETF). Section 2.1, "Name space specifications and terminology," describes the primary goal of the domain system is to provide a consistent name space for referring to resources, which includes the mapping of names to addresses.

3. Saltzer, J. H. (2018). 6.033 Computer System Engineering, Spring 2018 Lecture Notes, Lecture 16: Naming. Massachusetts Institute of Technology: MIT OpenCourseWare. Section 16.2, "Domain Name System (DNS)," explains that DNS's purpose is to map human-readable names to IP addresses, noting it is "the Internet's phone book."