Book Image

Linux Administration Cookbook

By : Adam K. Dean
Book Image

Linux Administration Cookbook

By: Adam K. Dean

Overview of this book

Linux is one of the most widely used operating systems among system administrators,and even modern application and server development is heavily reliant on the Linux platform. The Linux Administration Cookbook is your go-to guide to get started on your Linux journey. It will help you understand what that strange little server is doing in the corner of your office, what the mysterious virtual machine languishing in Azure is crunching through, what that circuit-board-like thing is doing under your office TV, and why the LEDs on it are blinking rapidly. This book will get you started with administering Linux, giving you the knowledge and tools you need to troubleshoot day-to-day problems, ranging from a Raspberry Pi to a server in Azure, while giving you a good understanding of the fundamentals of how GNU/Linux works. Through the course of the book, you’ll install and configure a system, while the author regales you with errors and anecdotes from his vast experience as a data center hardware engineer, systems administrator, and DevOps consultant. By the end of the book, you will have gained practical knowledge of Linux, which will serve as a bedrock for learning Linux administration and aid you in your Linux journey.
Table of Contents (15 chapters)

Listing firewall rules on the command line

Here, we're going to use both the newer method, firewall-cmd & ufw, for listing firewall rules, along with the older (but still popular) method, iptables. We're going to go into the basics of other tables within firewalls, and the storage location for rules.

Getting ready

Connect to your centos1 VM (and ubuntu1, if desired).

Enable and start firewalld for later examples:

$ sudo systemctl enable --now firewalld

How to do it...

While most of this book can be generalized to multiple distributions, firewalls are one...