Domain Name Servers or DNS for short is the Internet’s way to translation computer addresses to easy to remember names. For example if you had to type in 220.127.116.11 every time you wanted to view Facebook it would be a huge hassle.
In order for your computer to know what server address to connect a domain like Facebook.com to, there are servers that your computer connects to to get this information. These are called DNS servers and the most common provider of them is your Internet service provider. There are additional companies that provide this service but add a layer of protection by filtering out sites that are not family friendly.
You can make some simple changes to how your router is configured to take advantage of these services, there is no charge for them and it can be changed back very easily if you don’t want to continue to use them. One of these providers is a company called OpenDNS and you can find information on how to use their services here: