Geoblocking is a technology that is used to prevent access to web sites from visitors in particular countries or regions.

At the moment it is mainly used by traditional broadcast companies who are moving their television, radio and music content online. Because of distribution contracts with the producers of these programmes many broadcast web sites limit access to people with in their own country.

Whenever a person connects to the internet, their computer or mobile device is assigned what is called an IP address. This is a sequence of numbers in the form 255.255.255.255. The IP address is assigned to you by the internet service provider (ISP) that you are connecting through and these in turn are assigned to the ISP in blocks. It is therefore possible to say that a particular IP address is from a particular country or even city.

Site owners that want to use geoblocking simply choose to only allow access to a particular range of IP addresses or to block certain ranges.

This type of location based services can also be used to serve alternative content (e.g. with advertising) instead of just blocking the visitor.