OpenDNS is a DNS server that provides filtered DNS for free. DNS (Domain Name Service) is the system that lets your computer look up the address to a website that you type into your browser. For example if you type in www.google.com, DNS will tell your computer that to find the website it needs to retrieve data from the IP address: 216.58.217.132. It’s very much like an internet phonebook for your computer, tablet, or phone.

OpenDNS provides a means of filtering by essentially removing the IP addresses of undesirable websites from the phonebook. If you attempt to visit a blocked site, let’s imagine one called www.badsite.com, when using OpenDNS your computer will not be given the correct IP address. It will instead send you to a site stating that you are attempting to reach a site that has been blocked. OpenDNS does this for free, and without requiring any software installation.

It is important to remember that, like all filtering solutions, this cannot block all undesirable content. It only blocks sites that have been identified, and categorized as undesirable, by the efforts of OpenDNS.

New sites become available on the internet every day, and they won’t be blocked until they are identified and added to the list. Other sites that we consider acceptable can also provide content that we consider undesirable.

For example, a simple image search at www.google.com can easily display nudity. Or apps can download content from sources that don’t require the use of DNS at all.

Like every other filtering technique, OpenDNS is not a magic solution that will make our internet completely safe. Instead it is a free and fast means of blocking a significant amount of undesirable internet content. It is one tool among many that can help you keep your internet safe.