Firewalls are like a filter between your computer/network and potentially malicious data transmitted over the Internet. You can program what you want to get out and what you want to get in.
Firewalls can be used in a number of ways to add security to your home or business.
For business use: Large businesses often have very complex firewalls in place to protect their extensive communication/Internet network, and they can be configured in a variety of different ways. For example firewalls can prevent employees from sending certain types of emails or sending certain types of data to sources outside of the company’s network. They can also prevent employees from accessing certain types of websites, like social media sites. Firewalls can also prevent non-network configured devices from accessing certain data inside in the network.
For home use: The goal of a firewall is to protect your personal computer (and other devices connected to your home network) from malicious attacks – like viruses that can be transmitted onto your computer over the Internet via email, social media sites and more. If your devices are hit with a virus, it can quickly cause a lot of damage, potentially giving criminals access to everything stored in those devices – account usernames, passwords, banking information – anything thieves can use to carry out some form of identity theft. – including and more. Firewalls can be set up to prohibit all traffic unless it meets a specific set of criteria, or, it can allow all traffic except data that falls within a predetermined set of criteria.
Firewall Protection Services
ZoneAlarm is designed to protect your PC from hackers. This program includes four interlocking security services: a firewall, an application control, an Internet lock and zones. The firewall controls the door to your computer and allows only traffic that you understand and initiate. Cost: $39.95 and up -- the higher the price, the more features you get -- but the service does provide free antivirus and free firewall protection.
ZoneAlarm also offers mobile protection services for iPhones.
Comodo offers free Internet security, as well as virus and firewall protections for both PCs and Macs.
WinRoute Pro is a firewall, network address translator, router, cache-proxy server, mail server and scheduler all in one that can connect your network to the Internet through a single IP address. Cost: $49 or $79
Internet Security Systems
BlackICE Defender 2.1 delivers bulletproof intrusion detection and personal firewall protection to your PC. It scans your DSL, cable, or dial-up Internet connection looking for hacker activity, much like antivirus programs scan your hard disk looking for viruses. BlackICE Defender also claims to protect you in ways the other personal firewalls or antivirus software don't. Cost: $39.95-$49.95
Outpost is Agnitum's new firewall protection software. Jammer is also available on this site. Cost: $24.95 for Jammer; $39.95 for Outpost
For more options and reviews on different firewall protections, check out cnet.com.