A firewall is a software program designed to protect a computer or a network by preventing unauthorized users from gaining access or by monitoring transfers of information to and from the network or Internet.

Some operating systems, like Microsoft Windows Vista and Macintosh OS X, already include a firewall. Refer to the manual for your operating system for information and instructions on adjusting firewall settings. For your convenience, links to instructions for commonly used operating systems are provided below:

If your operating system does not have a firewall, or if you’d prefer to use a different firewall, then you will need to acquire third-party firewall software. Many Security Suites include firewall software, which can be customized to fit the way you use your computer. Links to information on several firewalls and security suites are provided below:

Be careful never use two firewall or two anti-virus products (or two suites that include them) at the same time. Completely uninstall one before installing another. Use the vendor’s uninstall utility or the add/remove software tool in your operating system’s control panel.

No matter if your firewall was provided with your operating system, or if you installed a third-party firewall, the settings can be adjusted to allow or block certain kinds of traffic or file transfers between your computer and your network or the Internet.

In some cases, if your firewall settings are too restrictive, your ability to download certain files or access certain web sites may be impaired. In other cases, if your firewall settings are not restrictive enough, certain kinds of undesirable traffic may gain to access your computer. For detailed information on adjusting the settings for your specific firewall, please consult the User Guide or contact the support department of your firewall manufacturer.