What is a Firewall?
Firewall is a programmable filter between your computer or network and the outside world. It inspects information coming from the Internet and compares it to a set of rules that you define. If a firewall finds the rules match, the information is allowed in; otherwise it is blocked. Firewalls help ward off various threats like malware, viruses, identity theft and online fraud.
Most personal computers and networks are exposed to numerous risks when they connect to other systems and the internet, making them easy targets for hackers, virus infections and other malicious mischief. When malware infiltrates your system, it can wreak havoc, corrupt files, steal personal information and more. Firewalls protect your computer and private network from such attacks by vetting all of the information that comes in and out of your computers and servers to prevent unwanted intrusions.
A basic firewall is usually installed on a home PC and works by scanning incoming and outgoing information for any signs of malware or other dangers. When it detects a threat, it either blocks the harmful activity or notifies you to take action.
A more sophisticated firewall, known as a proxy firewall, goes even further by reading and filtering application protocols rather than just IP addresses and ports. This type of firewall uses a’state table’ that remembers the behavior of different types of traffic to make decisions about what it should ‘learn’ and how it should respond in the future.