RHEL Linux Red Hat System Administration 2025 – 400 Free Practice Questions to Pass the Exam

The /etc/hosts file is a crucial component in the network configuration of a Linux system. Its primary purpose is to map hostnames to IP addresses. This means that when a hostname is referenced, the system first consults the /etc/hosts file to find the corresponding IP address before querying Domain Name Servers (DNS). This local resolution of hostnames can improve performance and ensure that systems can communicate even if DNS services are temporarily unavailable.

In many environments, especially smaller networks or for systems that do not need external DNS resolution, the /etc/hosts file allows administrators to manually define hostname-to-IP address mappings. Each entry typically consists of an IP address followed by the corresponding hostname and, optionally, aliases.

This functionality is foundational to network communication, as it allows users and applications to refer to systems by their hostnames rather than having to memorize and use their IP addresses. Such mappings are essential for many applications and services that rely on hostname resolution to function properly.