Book Image

Practical Linux Security Cookbook - Second Edition

By : Tajinder Kalsi
Book Image

Practical Linux Security Cookbook - Second Edition

By: Tajinder Kalsi

Overview of this book

Over the last few years, system security has gained a lot of momentum and software professionals are focusing heavily on it. Linux is often treated as a highly secure operating system. However, the reality is that Linux has its share of security ?aws, and these security ?aws allow attackers to get into your system and modify or even destroy your important data. But there’s no need to panic, since there are various mechanisms by which these ?aws can be removed, and this book will help you learn about different types of Linux security to create a more secure Linux system. With a step-by-step recipe approach, the book starts by introducing you to various threats to Linux systems. Then, this book will walk you through customizing the Linux kernel and securing local files. Next, you will move on to managing user authentication both locally and remotely and mitigating network attacks. Later, you will learn about application security and kernel vulnerabilities. You will also learn about patching Bash vulnerability, packet filtering, handling incidents, and monitoring system logs. Finally, you will learn about auditing using system services and performing vulnerability scanning on Linux. By the end of this book, you will be able to secure your Linux systems and create a robust environment.
Table of Contents (20 chapters)
Title Page
Copyright and Credits
Contributors
Packt Upsell
Preface
Index

Managing TCP/IP networks


As the size of a computer network grows, managing the network's information becomes an important task for the system administrator.

Getting ready

Before we start with making any changes in the TCP/IP configuration, make sure to create a backup of the Network Manager configuration file by using the following command:

Also make a backup of the /etc/network/interfaces file in the same way.

How to do it...

In this section, we will see how we can manually configure the network settings using the command line:

  1. Before starting with the manual configuration, first, let's check our current IP address, which has been assigned to the system automatically by DHCP. We can check the details graphically by right-clicking on the networking icon on the top-right panel and then selecting Connection Information, as shown in the following screenshot:

We can see that the current IP address of our system is 192.168.1.101.

  1. Next, we check the same information using the command line by typing in...