Book Image

Linux for System Administrators

By : Viorel Rudareanu, Daniil Baturin
Book Image

Linux for System Administrators

By: Viorel Rudareanu, Daniil Baturin

Overview of this book

Linux system administration is an essential aspect of maintaining and managing Linux servers within an organization. The role of a Linux system administrator is pivotal in ensuring the smooth functioning and security of these servers, making it a critical job function for any company that relies on Linux infrastructure. This book is a comprehensive guide designed to help you build a solid foundation in Linux system administration. It takes you from the fundamentals of Linux to more advanced topics, encompassing key areas such as Linux system installation, managing user accounts and filesystems, networking fundamentals, and Linux security techniques. Additionally, the book delves into the automation of applications and infrastructure using Chef, enabling you to streamline and optimize your operations. For both newcomers getting started with Linux and professionals looking to enhance their skills, this book is an invaluable hands-on guide with a structured approach and concise explanations that make it an effective resource for quickly acquiring and reinforcing Linux system administration skills. With the help of this Linux book, you’ll be able to navigate the world of Linux administration confidently to meet the demands of your role.
Table of Contents (21 chapters)
Part 1: Linux Basics
Part 2: Configuring and Modifying Linux Systems
Part 3: Linux as a Part of a Larger System

The hosts configuration file

The Linux hosts file is a simple text file that is used to map hostnames to IP addresses. It is located in the /etc directory. The file contains a list of IP addresses and their corresponding hostnames. When a user tries to access a hostname, the system checks the hosts file to determine the IP address associated with that hostname.

The hosts file is used first in the Domain Name System (DNS) server’s resolution process. If a hostname is not found in the DNS server, the system checks the hosts file for a mapping. This can be useful in situations where a specific hostname needs to be redirected to a different IP address or when you want to test a website before it is made live.

The hosts file consists of several columns of data, separated by whitespace. The first column contains the IP address, while the second column contains the hostname. Additional columns can be used to specify aliases for the hostname. For example, the following line in...