Copyright 2002 by
Prentice Hall, Inc.
8-18
Three techniques used by companies to protect themselves
n Firewalls:
Control access between networks
n Used to create
intranets and extranets, which only
employees and authorized business partners can access
n Implementation
nPacket filtering to block “illegal” traffic, which is defined by the security policy… or
nBy using a proxy server, which acts
as an intermediary
Security in the Internet Age: Countermeasures