Firewall Definition | The Interactive Glossary

A firewall allows only “safe” data from the Internet to flow in. This protects you from intruders or hackers who might try to break into your system via the Internet.

These days, most operating systems have built-in firewalls. You should make sure your firewall is enabled and up-to-date before connecting to the Internet.

Also See: Security Tips

Frequently Asked Questions

If I have a firewall installed, is my computer completely safe?

Nothing you do can make your computer completely safe, but having a firewall in place is a vital tool for increasing your device’s security. If your computer becomes infected by a virus or malware, your firewall can prevent the malicious software from utilizing your Internet connection to transmit confidential information to anyone else. A firewall can also prevent malicious access to your computer from an outside source. To ensure the highest level of protection, make sure you also have an up-to-date antivirus program running and always install the latest updates for your operating system.

Should I use a software- or hardware-based firewall?

If you only connect to the Internet with a single, home computer, a software-based firewall, such as the one included with most operating systems, should be all you need. However, if you run multiple computers and/or Internet-enabled devices, you may want to consider a hardware-based firewall in addition to your computer-based solution. For a home network, most routers include firewall components, which can be customized based on your usage. Many routers also include VPN functions, which allow you to connect to your home network from anywhere (even over public internet), and surf the Web securely from behind your home firewall. For business purposes, a dedicated firewall appliance may provide additional security.

How do firewalls know what information to let through?

For most home users, the operating system firewall comes with an established set of rules regarding what information can and cannot pass through it. When new information attempts to get through, for instance when a new program tries to utilize your Internet connection to upload or download information, you will be prompted by your computer to allow or deny this access. This typically happens when you are installing a new piece of software. If you trust that the software is safe, allow the connection. You can further customize your permissions manually, through your system’s firewall control panel, but this is only recommended for experienced computer users. The same goes for your router’s firewall settings.

For business-level firewall protection, a network administrator will set rules for the types of information that can pass through the firewall and for programs that are allowed to send and receive information. Firewall rules can be set based on a variety of variables, such as IP addresses, the port it is trying to use, the type of service being utilized, and values specific to the type of protocol being used.