firewall rule
compound.compound. a specific instruction that tells a computer network which traffic to allow and which to block. It acts like a security guard for your internet connection.
compound. a specific configuration setting within a network security system that determines whether to permit or deny traffic based on criteria like IP address or port number.
The administrator added a firewall rule to block the suspicious website.
After the security breach, the IT team updated every firewall rule to ensure only authorized employees could access the server.
Effective network security relies on a strictly ordered set of firewall rules, where more specific permissions are evaluated before a general 'deny all' instruction at the end of the list.
A compound of firewall, referring to a physical barrier designed to prevent the spread of fire between buildings, and rule, derived from the Old French 'riule' and Latin 'regula'. The term applies the logic of physical containment to digital network traffic.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Often used in the plural when discussing security policies; typically takes verbs like 'configure', 'implement', or 'bypass'.
Last updated July 22, 2026