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Using 'firewalld' for Advanced Packet Filtering
Managing a local firewall is something pretty much every Linux admin is going to have to do during their career. Many operating systems have adopted firewalld as the local firewall management system moving forward. Setting this up can lead to a more secure server and increase security through your environment.
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Table of Contents
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Challenge
Block SSH but allow HTTP
Use the
blockzone to filter on specific hosts and ports.You can run the following commands:
firewall-cmd --zone=block --add-source=10.0.1.101firewall-cmd --zone=block --add-service=httpYou can verify settings with:
firewall-cmd --info-zone=block -
Challenge
Allow ping
Since ping uses the ICMP protocol and not a specific port, we can't just add a port or service.
We need to use a rich rule:
firewall-cmd --zone=block --add-rich-rule='rule protocol value="icmp" accept'
What's a lab?
Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.
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Follow along with the author’s guided walkthrough and build something new in your provided environment!
Did you know?
On average, you retain 75% more of your learning if you get time for practice.
