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Firewall

FY-er-wawl /ˈfaɪərwɔːl/

nounB2GRESAT

technicalgeneral

A network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.

Acts as a barrier between a trusted internal network and untrusted external networks (like the internet), preventing unauthorized access.

The story behind the word. The word 'Firewall' originally referred to a physical wall constructed to prevent the spread of fire between buildings or sections of a building. In the 1980s, as computer networks became more interconnected, the term was adopted metaphorically. A network firewall acts as a digital 'wall' to prevent the spread of malicious data, unauthorized access, or cyber 'fires' from spreading into a private network, much like its architectural predecessor.

Word relationships

security barrier: A more general term for any security measure.
packet filter: Describes a core function of many firewalls.

open network: A network with no security restrictions.

Commonly confused with

Antivirus: A firewall controls network traffic; antivirus software detects and removes malicious programs already on a system.

Collocations

network firewall
software firewall
hardware firewall
configure firewall

Example sentences

"A robust Firewall is the first line of defense against cyber threats trying to access your computer or network." Discussing cybersecurity
"The IT department configured the corporate Firewall to block all unauthorized ports and suspicious IP addresses." Explaining network configuration

Memory hook

Imagine a literal wall of fire protecting your digital kingdom from invaders. A firewall does just that for your network. Digital fire wall

When not to use

Do not use 'firewall' to refer to antivirus software; while both are security tools, a firewall focuses on network traffic control.

Fun facts

The first commercial firewall product was developed in the late 1980s.
Many operating systems, like Windows and macOS, include built-in software firewalls.