What Is a Firewall?
A firewall is a security device that protects networks from threats. There are several different types of firewalls, each with its own unique features. Some are more powerful than others, and some are designed to keep certain types of traffic out entirely. For example, packet filtering firewalls may block packets that match specific criteria, such as a virus. Another type of firewall is a stateful inspection firewall, which analyzes traffic with a higher level of context.
Firewall rules need to be carefully designed and optimized. Cleaning up the firewall rule base and deleting redundant or unnecessary rules can improve network security. Shadowed rules and duplicate rules slow down the firewall, and errors in firewall rules can cause the firewall to malfunction. Firewalls are the first line of defense against security threats.
Throughout history, multiple creators have worked on firewall technology. The first stateful inspection firewall was introduced in 1993 by Gil Shwed. Later, Check Point Technologies introduced the FireWall-1 firewall. In 2000, Netscreen released a purpose-built firewall called ‘Appliance.’ Since then, purpose-built firewalls have gained widespread adoption in enterprises.
A firewall acts as a gatekeeper between an external network and a guarded one. It analyses incoming packets and decides whether they are harmless or malicious. It does this by checking the sender’s IP address and content. This way, it can detect malicious or unwanted traffic and block it.