How Firewalls Work: A Comprehensive Guide to Network Security Gatekeepers
Firewalls serve as the first line of defense in network security, monitoring and controlling incoming and outgoing traffic based on predefined rules to block unauthorized access.[1][2][8] This detailed guide explores the mechanics of firewalls, from basic packet filtering to advanced stateful inspection, helping you understand how they protect networks in today’s threat landscape.[3][5] What is a Firewall? A firewall is a network security system—either hardware, software, or a combination—that acts as a gatekeeper between trusted internal networks and untrusted external ones, like the internet.[2][5][6] It inspects all data packets entering or leaving the network, deciding whether to allow, block, or log them based on security policies.[1][3] ...