What is a Firewall?
Firewall is a type of cybersecurity system that is installed on an organization’s network to protect against external threats. It works by analyzing data packets against predefined security rules to allow or block them. It can be used to protect against unauthorized access, data leakage, and other cybersecurity threats. Firewall can be either a standalone application or a software component of a larger cyber security solution.
Firewalls can be deployed on network edges to guard against unauthorized connections or in the center of the network to create a secure environment with segmentation and to guard against insider threats. They can also be cloud-native to enable agile and elastic security.
Originally, firewalls were developed in the 1980s by American technology companies such as Cisco Systems and Digital Equipment Corporation. These early “network layer” firewalls judged data packets based on their apparent source and destination IP addresses, ports, and protocol. They were fast and transparent, but they could be easily foiled by attackers.
The next generation of firewalls, known as stateful inspection firewalls, improved on this by storing information about previous interactions with data packets in a state table. These firewalls allowed or blocked traffic based on the state table and could be more effective against different types of attacks.
More advanced firewalls rely on strong passwords or multifactor authentication for users to log in, and they provide user permission control to limit who can change the firewall configuration. They also perform logging and audit functions to detect any unwarranted changes to the configuration and help administrators recover from them. The resulting logs can be used to identify patterns and improve the rule set for better defense against new cyberattacks.