Network layer firewall: Difference between revisions

Revision as of 16:44, 10 November 2003

Revision as of 03:27, 18 April 2004

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Network layer firewalls generally fall into two sub-categories, [[stateful firewall|stateful]] and [[stateless firewall|non-stateful]]. Stateful firewalls hold some information on the state of connections (for example: established or not, initiation, handshaking, data or breaking down the connection) as part of their rules (e.g. only hosts inside the firewall can establish connections on a certain port).

Stateless firewalls have packet-filtering capabilities but cannot make more complex decisions on what stage communications between hosts have reached. Stateless firewalls therefore offer less security. Stateless firewalls somewhat resemble a [[router]] in their abiltyability to filter packets.

Any normal computer running an [[operating system]] which supports packet filtering and [[routing]] can function as a network layer firewall. Appropriate operating systems for such a configuration include [[Linux]], [[Solaris Operating Environment|Solaris]] and the [[Berkeley Software Distribution|BSD]]s.