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Annotated edit history of FireWall version 4 showing authors affecting page license. View with all changes included.
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4 AristotlePagaltzis 1 A network device through which network traffic passes, such as (commonly) a router/gateway or (sometimes) a bridge/switch, which can filter or otherwise impose arbitrary restrictions on the traffic. It can therefore be used to present a hurdle for someone sitting on one side of the FireWall and trying to do something unwelcome or malicious to a system on the other side. Commonly, a FireWall is more permissive in one direction than the other, thus yielding an inside-vs-outside-the-FireWall configuration. The actual FireWall can be implemented in software (the usual case with routers) or hardware.
1 WikiAdmin 2
4 AristotlePagaltzis 3 Dividing the network in this manner is both useful and problematic:
2 ChrisLowth 4
4 AristotlePagaltzis 5 * It’s useful because it can provide a single hardened entry control point which effectively prevents initial attacker reconnaissance. It also prevents direct access to internal systems which might run services for whom a new exploit was just published, buying time for the administrator(s) to secure the systems.
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7 * It’s problematic because a lot of threats are internal, and as such entirely outside the scope of FireWall protection. A FireWall also ''must'' permit at least certain traffic (otherwise it’d be more effective to just cut the connection). Therefore, a FireWall can be no license for neglecting to keep ''every single'' machine on the network secure.
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9 A FireWall is an effective and financially efficient time-buying measure that protects the systems you control from falling victim to attacks you didn’t have the chance to learn about yet; not more.
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11 See also:
12 * HowFirewallingWorks
13 * FirewallNotes
14 * FirewallingPeerToPeer
15 * PerrysFirewallingScript