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====== How Firewalls Work ======

See also:  [[software:Computer Security]], [[software:Software Categories]]

FIXME

**This probably should be a blog post rather than on the Wiki.**


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title: Firewall - Blocking computers

Original date: 2008/05/15 09:53

tags: linux, operating system, draft

description: Info on Firewalls.

If you've seen my article on How computers talk to each other (originally http://tim.tbruce.com/node/47 and now http://www.tbruce.com/posts/how_computers_talk.html), you already have some background. If you haven't read that yet, please read that now.

Since computers require a port to talk to as well as an address, a firewall can do a variety of things to prevent the communication from occurring:

  * It can set it on (or off)
  * It can block it
  * It can look at the data being sent and make a decision to block or send it on
  * It can look at other information in the packet being transmitted and make a decision