Q. I heard you mention that you use OpenDNS at home to stop your son from wandering into bad places online. You said it can also speed up Web surfing. Can you tell me more about how it works?
—Bobbie in Boston, listening on WBZ 1090 AM

A. To understand how OpenDNS works, we need to have a little Internet lesson. Ready?

To locate Web sites, computers use IP numbers. But numbers like 66.210.246.140 are difficult to memorize. That's where DNS (domain name system) comes in. DNS allows us to use names like www.komando.com instead of numbers.

Behind the scenes, computers still work with IP numbers. Lists of matching names and numbers are kept by DNS servers. Enter an address, and your browser requests the matching number from a DNS server.

This lookup process takes time. DNS servers typically keep only partial lists. Often, one request is forwarded through several servers. Many are halfway around the globe.

OpenDNS is a free service that accelerates this process. OpenDNS servers keep more complete lists than other DNS servers. Also, your browser's requests go to the OpenDNS server closest to you.

You don't have to download anything to use OpenDNS. You simply change settings on your computer. The OpenDNS site includes instructions for changing these settings in Windows. There are also instructions for those who connect through routers.