What Is a Firewall?
Firewalls protect networks from attacks by examining data packets in context to determine whether to allow or block traffic. They can be hardware or software, and may be standalone or embedded in other network devices. Typically, they filter and monitor both inbound and outbound traffic and help secure sensitive data, enabling organizations to meet regulatory compliance requirements and safeguard customer information.
A firewall can either be part of your device, like the built-in firewall in a computer or home network, or can be software running on a server, such as a Virtual Firewall (FWaaS). Most devices, including PCs and smartphones, have a basic built-in firewall to help prevent unwanted connections to unsecure ports.
While firewalls are critical for most environments, they can also be a source of security breaches and attacks. To maximize security, follow best practices for installing, updating, and maintaining firewall solutions. These include disabling insecure protocols, implementing a consistent update process, and keeping logs backed up to mitigate vulnerabilities. A consistent review of firewall configurations and policies is also recommended to identify misconfigurations that could leave your network vulnerable.
Firewalls have come a long way since the late 1980s, when they began as simple packet filters that evaluated data packets based on criteria such as source and destination IP addresses, ports, and communication protocols. By the 1990s, stateful inspection was introduced to analyze data packets more holistically by taking into account the entire history of each device and connection. This improved contextual awareness significantly boosted security. Today’s advanced NGFWs leverage artificial intelligence to improve detection of unknown and evasive threats, making them more effective than legacy systems.