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Firewalls

A good security plan uses layered defenses, including hardware and software firewalls. Firewalls work in three ways:

Packet filtering: Packet filtering is the most common and straightforward. Firewalls that use packet filtering either block or allow packets by using basic criteria, source or destination IP addresses, ports, or protocols. The disadvantage of packet filtering is that it is not subtle. It is a reliable but inflexible gate guard. Sometimes legitimate packets get filtered because they are different.

Proxy filters: Advocates for a kinder, gentler network community allow packets of all persuasions to enter or leave and use more-sophisticated rules. These proxy filters are really more concerned about network intrusion than about internal issues.


  

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