Definition of firewalls Firewalls

We found 3 definitions of firewalls from 2 different sources.

What does firewalls mean?

Wiktionary

firewalls (Noun)
Plural of firewall.

Part of speech

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firewalls, noun, plural of firewall.

WordNet

Noun Plural: firewalls
firewall - (colloquial) the application of maximum thrust; "he moved the throttle to the firewall"
		driving force, thrust, drive verbal criticism; "he enlivened his editorials with barbed thrusts at politicians"
firewall - (computing) a security system consisting of a combination of hardware and software that limits the exposure of a computer or computer network to attack from crackers; commonly used on local area networks that are connected to the internet
		security system an electrical device that sets off an alarm when someone tries to break in
firewall - a fireproof (or fire-resistant) wall designed to prevent the spread of fire through a building or a vehicle

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Wiktionary

firewall (Noun)
A fireproof barrier used to prevent the spread of fire between or through buildings, structures, electrical substation transformers, or within an aircraft or vehicle.
firewall (Noun)
The software that monitors traffic in and out of a private network or a personal computer and allows or blocks such traffic depending on its perceived threat.
firewall (Verb)
To protect with a firewall.
firewall (Verb)
To block with a firewall.
firewall (Verb)
To use maximum acceleration.

OmegaWiki DictionaryOmegaWiki Dictionary Ω

firewall
A service which functions in a networked computing environment to prevent the communications forbidden by a security policy.
firewall
A type of fire separation of noncombustible construction that subdivides a building or separates adjoining buildings to resist the spread of fire.

Wikipedia

networking
Originally, a "firewall" was a wall that was built to stop (or slow down) the spread of a fire. In terms of computer security, a firewall is a piece of hardware or software. The firewall is there to look at the traffic passing through it. Based on a set of rules, traffic can be allowed, or it can be blocked. A firewall therefore protects one part of the network against unauthorised access.

Packet filtering.

Data travels on the internet in small pieces; these are called packets. Each packet has certain metadata attached, like where it is coming from, and where it should be sent to. The easiest thing to do is to look at the metadata. Based on rules, certain packets are then dropped or rejected. All firewalls can do this.

Stateful packet inspection.

In addition to the simple packet filtering (above) this kind of firewall also keeps track of connections. A packet can be the start of a new connection, or it can be part of an existing connection. If it is neither of the two, it is probably useless and can be dropped.

Application-layer firewalls.

Application-layer firewalls do not just look at the metadata; they also look at the actual data transported. They know how certain protocols work, for example FTP or HTTP. They can then look if the data that is in the packet is valid (for that protocol). If it is not, it can be dropped.

Tunnelling.

Firewalls can provide a secure connection between two networks. This is called "tunneling". The data may be encrypted. It is unencrypted at the