The mechanical engineer, who lives near Toronto, recently documented 30 attempts to gain access to his PC through his high speed DSL connection during a single week. They can cause your system to reboot or not talk properly to the Internet. 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 manoeuvre more smoothly in the rapid flow of data and are more 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 behaviour. As an additional protection, these firewalls enable home computers to switch into stealth mode so that they are invisible to the bad guys. BlackICE Defender, another popular firewall product, takes a slightly different approach and focuses more heavily on intrusion detection.