FIREWALL – A firewall is software or firmware that prevents unauthorized access to a network. It inspects incoming and outgoing traffic using a set of rules to identify and block threats. Firewalls are used in both personal and enterprise settings, and many devices come with one built-in, including Mac, Windows, and Linux computers. They are widely considered an essential component of network security. Firewalls are important because they have had a huge influence on modern security techniques and are still widely used. They first emerged in the early days of the internet, when networks needed new security methods that could handle increasing complexity. Firewalls have since become the foundation of network security in the client-server model – the central architecture of modern computing. Most devices use firewalls – or closely related tools – to inspect traffic and mitigate threats. Firewalls are used in both corporate and consumer settings. Modern organizations incorporate them into a security information and event management (SIEM) strategy along with other cybersecurity devices. They may be installed at an organization’s network perimeter to guard against external threats, or within the network to create segmentation and guard against insider threats. A firewall establishes a border between an external network and the network it guards. It is inserted inline across a network connection and inspects all packets entering and leaving the guarded network. As it inspects, it uses a set of pre-configured rules to distinguish between benign and malicious packets.