IP2Location

IP2Location is a database-driven solution to identify visitors' geographical location such as their location (country, region, city, latitude, longitude, ZIP code, time zone), connection speed, ISP and domain name using their IP addresses. The technology is also known as IP geolocation. The solution is platform independent and can be integrated by almost all database systems such as mySQL, MS-SQL Server or others. The solution also comes with API in several programming languages .NET, Java, C, C++, Visual Basic, PHP, ColdFusion , Perl, Ruby and Python. IP2Location has been used by many other applications such as Wikiscanner.

Accuracy and criticism
Critics note that geolocation software is inherently inaccurate and conflicts with the global nature of the Internet.

IP2Location claims that they can retrieve up to the zip code related to an IP address, helping for example to fight fraud on the Internet. In fact, it appears during any test that the zip code and other related informations are the ISP zip code and headquarters, not the physical location of the computer really using the IP address.

In European countries, the difference between real physical location and the position given by IP2Location can be as high as 1000 kms, so the accuracy is really bad in most cases. For example, all IP addresses from Orange and Proxad ISP in France (first and second biggest ISP in France) are reported to be always in Paris, whatever the real position is. A simple IP spoof program can then easily fool the IP2Location system.

Research was done by the University of Toronto on this topic.