This beginner-level course explains what is firewalld and teaches you basic configurations to secure your system. But even the so-called IT experts drawing huge salaries do not know anything about firewald configuration, and this is why you see news where systems are routinely compromised. IT managers and administrators refuse to learn new technologies, and whatever little they know is shared amongst their colleagues. As soon as someone leaves a company, small organizations, everything is in disarray. I have seen customers screaming at the vendors because they did not get the administrator's password from the old employees. Please do not heed headless and illogical reviews saying that this is an introductory course, and such people would not be able to start firewalld and never seen a Centos system. This is a free course and will meet your expectations, but if you are the complaining jobless type, you will never succeed in life anyway, and you are NOT welcome to take this class. I have a tip for those who have a habit of collecting free courses, should you not try to work on basic English, first? Do not collect free courses, first finish one course and then jump onto another. You will never ever learn if you do not read the books I have attached with my courses.