There are many words and phrases used when talking about computers or the Internet and if you think the word firewall means using your computer while jumping through a hoop of flames you would be sorely mistaken. Firewalls, when discussing the Internet and computers actually refers to the way networks are kept secure.
Computer related firewalls are either hardware-based or software-based and the primary objective of firewalls is to control incoming and outgoing network traffic done so through analyzing data packets while also determining whether or not a certain data packet should be allowed through the firewall or not, which is based on rule sets that are predetermined.
Network firewalls build brigades between internal networks and other external networks like the Internet that assume they're trusted and secure. Most operating systems found on personal computers in a home will come equipped with their own software-based firewalls that will make sure your computer is protected against any threats that may come from the Internet. In addition to operating system firewalls many anti-virus protection software programs such as Norton will also come with their own firewall protection system for that added punch of extra security.
May we suggest: The Evolution of the Firewall
There are numerous firewall techniques out there that do their best to block unwanted or unsecured data packets from accessing private networks or public networks and they include packet filters, application gateways, circuit-level gateways and proxy servers.
A packet filter looks at every packet that enters or leaves the network and will either accept or reject them based on user-defined rules. Packet filtering is pretty effective in doing its job while also being transparent to users on networks at banks that are more knowledgeable than firewalls. The only drawbacks to packet filters are that they're difficult to configure and susceptible to IP spoofing. Application gateways apply security mechanisms but might impose performance degradation. Circuit-level gateways do the same thing as application gateways once a connection has been made and that in turn allows data to flow between hosts without further checking being required. Proxy servers intercept all messages that leave or enter the network and can hide true network addresses.
Now that you know about firewalls and how they're the first line of defense in protecting your information you should feel more secure when it comes to everything you look at on the Internet.