The Domain Name System is nowadays being (mis)used by CDNs to map user resquests to appropriate servers. DNS is therefore the central mechanism through which the location from which content is obtained is being chosen. Despite its widespread use for several decades, the behavior of DNS deployment within ISP networks is still poorly understood. In this work, we measure the performance of DNS from a large set of vantage points inside commercial ISPs, and analyze its consequences on the CDN server selection mechanism.

Content is king in today's Internet. Most of the traffic exchanged in the Internet relates to content whose popularity changes very fast over time. Due to the large amount of traffic that has to be delivered, content delivery platforms are delivering content from multiple locations, typically data-centers, as well as deployed caches deep within ISP networks to go around network bottlenecks. To better understand the way content is Before being able to understand how dynamic Internet content is, we need to find out where the servers that host it are, and how different applications that manage content decide how to map content to their servers. In this work, we rely on active measurements to map the infrastructure hosting content in the Internet.

IP Geolocation consists in finding the geographic location of an IP address in the Internet. There are two methods: passive (geolocation databases) and active (active measurements). Geolocation databases are known to have limited accuracy, while active measurements place burden on the network and require distributed measurements infrastructures. Both methods have limited accuracy, but their actual accuracy has been understudied in the literature, especially for geolocation databases. In this work, we investigate the accuracy of geolocation databases based on ground truth information, and find that their accuracy is very limited at the country-level.

• Ingmar Poese
• Georgios Smaragdakis

• Bernhard Ager
• Steve Uhlig