The easiest way to protect yourself is to get a personal firewall. Free firewalls are also available. While dial-up users are also at risk of unwanted digital visitors, broadband users are more vulnerable. Intruders can maneuver more smoothly in the rapid flow of data and are more likely able to escape notice. Because computers with broadband connections are assigned an Internet address that is either fixed, or within a narrow range of known addresses, they are also easier for troublemakers to locate.
Personal firewalls work in two ways.
They monitor electronic traffic that is entering and exiting a machine, and they sound an alarm when they detect unfriendly behavior. As an additional protection, these firewalls enable home computers to switch into stealth mode so that they are invisible to bad guys. BlackICE Defender, another popular firewall product, takes a slightly different approach and focuses more heavily on intrusion detection. All major firewall products do this to some extent by logging attempts to connect to a machine and flagging connections that look suspicious. But BlackICE Defender has developed some of the most sophisticated information about intruder activity.