Looking glass servers show inconsistent geolocation accuracy worldwide
Through the Looking Glass: Analyzing Geolocation Providers Using Looking Glasses and Active Measurements
Networking and Internet Architecture
Summary
Sometimes it’s useful to know exactly where a server is located, especially when troubleshooting internet problems. This study checked almost 4,500 special servers called Looking Glass servers, which help measure internet connections from many places. The researchers found that many of these servers are not located where some geolocation services say they are. They also found differences between several location databases, with one called IPinfo being the most accurate for these servers.
What this means in practice
- •For network operators: Verify the actual locations of Looking Glass servers to improve network troubleshooting accuracy using combined RTT and geolocation checks.
- •For internet service providers: Improve accuracy of IP geolocation services for customers by integrating findings on the reliability of popular geolocation databases.
Authors
William Leung, Oliver Gasser
Abstract
Looking Glass servers (LGs) allow users and network operators to debug issues or measure performance to/from arbitrary, external IP addresses, making LGs a valuable tool in a variety of analyses. To assess the reliability of LGs as an independent and free set of vantage points, we perform an analysis of 4487 LG servers across 144 countries. We analyze LGs by comparing them to six different geolocation databases from four providers, and by conducting active measurements on LGs. In our RTT measurements we find 9 of 18 LG providers have at least one server with an RTT-disconfirmed location. We also find substantial differences between geolocation databases' ability to locate LGs, with IPinfo showing the closest distance to LGs.