What Is a Firewall?
Firewall is a software or hardware that builds a protective barrier between a trusted internal network and untrusted external networks like the Internet, blocking or inspecting data packets. This keeps out malicious traffic and other threats while allowing essential data to flow.
It’s important to have a firewall because it protects your devices and network from unauthorized access and different kinds of cyber threats, like hacking, ransomware, malware, and online fraud. Without protection, your data and devices are exposed to cyberattacks that can threaten your productivity or compromise sensitive information.
To keep your devices and networks protected, set strict firewall policies to meet your business’s security needs. Follow the principle of least privilege, granting users only the minimum level of access needed to do their job, and regularly conduct security audits and tests. Also, implement strong passwords and multifactor authentication to reduce the risk of compromised credentials and limit who can change firewall rules.
The most common types of firewalls are packet filtering, stateful inspection, and application-layer firewalls (proxy firewalls). Packet filters examine the data packets that enter your network to make decisions about what to allow or block based on criteria like source/destination IP, ports, and protocols. Stateful inspection firewalls keep track of active network connections, enhancing their decision-making capabilities. Application-layer firewalls, such as proxy firewalls, operate at the OSI model’s application layer and offer deeper, more sophisticated filtering and content inspection capabilities. Next-generation firewalls (NGFW) combine traditional firewall capabilities with advanced features like application awareness and integrated intrusion prevention systems to create a single solution that can defend against modern threats at multiple layers of the network perimeter.