Firewall and packet filters

A firewall is a network security device that monitors and filters incoming and outgoing network traffic based on your organization's pre-determined security policies. Basically, a firewall is basically a barrier between your private internal network and the public Internet.

Packet filtering is a firewall technology used to monitor outgoing and incoming packets and control network access by allowing or stopping packets based on source and destination IP addresses, protocols, and ports.

Firewalls have been the first and most reliable line of defense in network security for over 30 years. Firewalls first appeared in the late 1980s. They were initially thought of as packet filters. These packet filters were nothing more than network settings between computers. The main function of these packet filtering firewalls was to look for packets or bytes sent between different computers. Although firewalls are becoming more sophisticated due to ongoing development, such packet filter firewalls are still used in legacy systems. When technology was introduced, GilShwed of Check Point Technologies introduced the first stateful inspection firewall in 1993. It was named FireWall1. In 2000, Netscreen released a dedicated firewall appliance. With faster internet speeds, lower latency, and higher throughput at lower cost, it became popular and was quickly adopted by businesses.

How a Firewall Protects a Network?

The firewall system analyzes network traffic based on predefined rules. Then filter the traffic to prevent it from coming from untrusted or suspicious sources. Allow only inbound traffic that is configured to accept. Normally, a firewall intercepts network traffic at a computer entry point called a port. Firewalls perform this task by allowing or blocking certain data packets (a unit of communication sent over a digital network) based on predefined security rules. Inbound traffic is only allowed from trusted IP addresses or sources.