Book Image

Practical Linux Security Cookbook

By : Michael A Lindner, Tajinder Kalsi
Book Image

Practical Linux Security Cookbook

By: Michael A Lindner, Tajinder Kalsi

Overview of this book

With the growing popularity of Linux, more and more administrators have started moving to the system to create networks or servers for any task. This also makes Linux the first choice for any attacker now. Due to the lack of information about security-related attacks, administrators now face issues in dealing with these attackers as quickly as possible. Learning about the different types of Linux security will help create a more secure Linux system. Whether you are new to Linux administration or experienced, this book will provide you with the skills to make systems more secure. With lots of step-by-step recipes, the book starts by introducing you to various threats to Linux systems. You then get to walk through customizing the Linux kernel and securing local files. Next you will move on to manage user authentication locally and remotely and also mitigate network attacks. Finally, you will learn to patch bash vulnerability and monitor system logs for security. With several screenshots in each example, the book will supply a great learning experience and help you create more secure Linux systems.
Table of Contents (17 chapters)
Practical Linux Security Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Configuring and using the TCP Wrapper


Securing a server by restricting access is a critical measure, which should never be avoided while setting up a server. Using TCP Wrappers, we can allow only those networks to have access to our server's services that we have configured and support TCP Wrappers.

Getting Ready

To demonstrate these steps, we use two systems that are on the same network and can ping each other successfully. One system will be used as the server and the other as the client.

How to do it?

Linux provides several tools to control access to network services. TCP Wrappers is one among those and adds an additional layer of protection. Here, we will take a look at how to configure TCP Wrappers to define access for different hosts.

  1. First, we need to check whether a program supports TCP Wrappers or not. To do this, first find the path of an executable program using the which command:

    which sshd
    

    Here, we have used the SSH program as an example.

  2. Next, we use the ldd program to check the compatibility...