linux

Objectives

• Troubleshoot linux systems following a number of steps iteratively until solutions are found
• Check network and file integrity for possible issues
• Resolve problems when there is system boot failure
• Repair and recover corrupted filesystems
• Understand how rescue and recovery media can be used for troubleshooting

Troubleshooting Overview

• Beginner
• Experienced
• Wizard

Basic Techniques

• Characterize the problem
• Reproduce the problem

Objectives

• Understand what firewall are and why are they useful
• Know the tools to control the firewall 
• Be familiar with firewalld and firewall-cmd program
• Know how to work with zones, sources, services and ports

What is a Firewall

Is a program that monitors and controls data packages for both incoming and outgoing network connections, allowing or denying communication according given configurations.

These can be either hardware or software based tools, that can be found in the network routers as individual computers.