Firewalls and VPNs

Firewalls and Virtual Private Networks (VPNs) are two cornerstones of network security. A firewall acts as a security guard at the perimeter of a network. Its fundamental job is to inspect network traffic passing through it and decide whether to allow or block it based on a set of security rules. The simplest type is a packet-filtering firewall, which examines the headers of packets (source/destination IP, port, protocol) and makes decisions based on simple rules. More advanced firewalls, known as stateful inspection firewalls, track the state of active connections and can make more intelligent decisions. Next-generation firewalls (NGFWs) add even more capabilities, such as deep packet inspection (DPI) to examine the payload of the packet, application awareness, and integrated intrusion prevention. A VPN is a technology that extends a private network across a public network, like the internet. It allows users to send and receive data as if their devices were directly connected to the private network. VPNs are crucial for secure remote access, enabling employees to work from home and connect securely to the corporate network. They are also used to connect different office locations securely over the internet (site-to-site VPN). A VPN works by creating an encrypted tunnel. All traffic from the user's device is encapsulated within a standard protocol and encrypted before being sent over the public network. At the other end, the VPN gateway decrypts the traffic and forwards it to the private network. This ensures confidentiality and integrity, protecting the data from eavesdropping.