Firewalls

the firewall down to the bare essentials needed for the purpose of the

network it is trying to protect.

In addition to these tools, many types of scanners are available for

download from reputable sites. Things such as port scanners, testers,

and IP range scanners are very common and, if investigated care-

fully, can add a valuable resource to any administrator’s toolbox.

Care must be taken, however, because hackers have been known to

post infected tools—they know that administrators want to use the

same tools they use to test their systems. Creating fake tools that are

actually Trojans and worms to be downloaded by system adminis-

trators is yet another ...