Computer firewalls, if properly used, can keep your computer safe from harm by setting up filters to detect and block intrusion attempts from hackers on the Web, or on any other network, public or private. Firewalls can also track and keep logs of attempts to access the network, adding to their security functions.
Firewalls can block intruders by looking for suspicious words, domain names or IP addresses. Other methods include blocking certain protocols like FTP, ports or routing through a proxy service.
There are hardware and software firewalls. Hardware firewalls are usually found in routers, which distribute incoming traffic from an internet connection to computers. Software firewalls reside in the individual computers.
Firewalls prevent malicious programs from accessing and damaging your computer. Software firewalls provide another layer of security. They also prohibit malware on your own computer from being sent to others.
While firewalls are essential for anyone on a network, particularly the Internet, at times they can block legitimate transmission of data and programs.
Operating on the Internet without a firewall is akin to leaving the front door of your home open with a sign reading "Rob Me."