What is the primary function of a firewall? What are the general rules for employing packet filtering?

What precisely does a firewall system do, particularly one that is given the greatest priority?What is the perfect way to utilize your packet filtering software and what are the best practices for doing so?

What precisely is the purpose of a firewall system, particularly one that is categorized as critical?How should your packet filtering software be utilized optimally, and what are the best practices?

When it comes to protecting a network, what function does a firewall perform above all others?When and how should packet-filtering software be used, and what criteria should be used?