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What is Firewall Rules?

Configuration entries that define which network traffic is allowed or blocked based on source, destination, port, and protocol.

Firewall rules specify allow/deny decisions based on traffic attributes: source IP, destination IP, port number, protocol (TCP/UDP), and direction (inbound/outbound). Rules are processed in order — first match wins.

Best practices include default-deny (block everything, explicitly allow needed traffic), least privilege (minimal ports open), logging denied traffic, separating inbound/outbound rules, and regular rule review. Cloud security groups function as virtual firewalls with similar rule structures.

Related Terms

Two-Factor Authentication (2FA)
A security method requiring two different forms of identification before granting access to an account.
DAST (Dynamic Application Security Testing)
Testing a running application from the outside by sending malicious requests to discover security vulnerabilities.
RBAC (Role-Based Access Control)
An access control model where permissions are assigned to roles, and users are assigned to roles rather than getting permissions directly.
SIEM (Security Information and Event Management)
A platform that collects, correlates, and analyzes security events from across an organization to detect threats and incidents.
Zero Trust
A security model that requires strict identity verification for every user and device, regardless of their network location.
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