What is the purpose of the /etc/hosts file?

The purpose of the /etc/hosts file is to provide a mapping of IP addresses to hostnames. This file acts as a local mechanism for resolving hostnames into their corresponding IP addresses without the need to query a Domain Name System (DNS) server. When a system tries to resolve a hostname, it first checks the /etc/hosts file to find a corresponding IP address. This is particularly useful for quick lookups, as it reduces reliance on network-based DNS queries.

The contents of this file typically consist of a list of IP addresses followed by their respective hostnames. By defining these mappings, systems can resolve hostnames quickly, even if they are not on the network or if DNS services are temporarily unavailable.

The other options relate to different functionalities: DHCP configuration deals with dynamic IP assignments, static routes are about defining paths for traffic on a network, and caching DNS queries pertains to storing recently resolved hostname-to-IP mappings temporarily to enhance lookup speed in future queries. None of these functions are related to the primary purpose of the /etc/hosts file, reinforcing why the correct answer focuses on its role in hostname resolution.