What is a Firewall?
Firewall is a set of rules that monitors incoming and outgoing network traffic to detect and block threats. They are the first line of defense against malicious software and other external threats to your business network. Firewalls can be implemented as either permissive or restrictive. Permissive firewalls allow any service unless explicitly denied; restrictive configurations drop all services. Firewall design policies are based on your specific security needs and the threats you face.
Firewalls can be hardware or software. The latest version of Windows includes a built-in firewall, and most routers also include a built-in firewall that you can enable for protection. There are several different types of firewalls on the market, including packet filtering, stateful inspection, and application layer filters. These later types can analyze the payload of a packet to detect if a legitimate request is being masked by malware or a malicious protocol. However, they tend to be more expensive in terms of computing resources.
The need for a multilayer approach led to the fourth generation of firewalls, called next-generation firewall (NGFW). These combine traditional capabilities with new technologies like advanced threat detection and application awareness. It is important to ensure your firewalls are updated regularly with patch releases to defend against the latest vulnerabilities and threats. Additionally, a regular process for reviewing and monitoring your firewall logs can help you identify suspicious activities that may indicate unauthorized access to the system. It is also important to limit the ability for users to alter the firewall configuration.