Seminar Details
2025-11-10 (11:00) : Double seminars by Hugo Rimlinger (LIP6) & Moritz Müller (université de Twente)
At Shannon room, Maxwell building
Organized by Computer Science and Engineering
Section 1: GeoResolver: An Accurate, Scalable, and Explainable Geolocation Technique Using DNS Redirection
Speaker :
Hugo Rimlinger (LIP6)
Abstract :
Obtaining an accurate, explainable and Internet scale IP geolocation dataset has been a longstanding goal of the research community. Despite decades of research on IP geolocation, no current technique can provide such a dataset. In particular, latency-based geolocation techniques do not scale, because, on one hand, we have thousands of available vantage points to perform measurements, but on the other hand, we have no way to select the right ones for each IP address. In this paper, we present GeoResolver, which is a serious step towards our goal, by using the idea that when multiple operators redirect two prefixes to the same servers, these prefixes should be close to each other. With this intuition, we define a methodology to measure and compare the redirection of prefixes to servers using ECS DNS measurements, and select the prefixes with the smallest redirection distance to a target prefix to issue the latency measurements to targets in that prefix. GeoResolver performs nearly as well as a brute force approach, geolocating 94% of the targets that could actually be geolocated at metro level, while using 4.3% of the probing budget compared to the state of the art. On the Internet scale CAIDA ITDK dataset, GeoResolver geolocates 16% of the IP addresses at metro level, 3.4 times more than the state of the art. In addition, GeoResolver is robust to public resolvers or hypergiants stopping supporting ECS.
Section 2: Monitoring highly distributed DNS deployments: challenges and recommendations for the root server system
Speaker :
Moritz Müller (Université de Twente)
Abstract :
DNS name servers are crucial for the reachability of domain names. For this reason, name server operators rely on multiple name servers and often replicate and distribute each server across different locations across the world. Operators monitor the name servers to verify that they meet the expected performance requirements. Monitoring can be done from within the system, e.g. with metrics like CPU utilisation, and from the outside, mimicking the experience of the clients. In this talk, we focus on the latter. We take the root server system as a use case and highlight the challenges operators and researchers face when monitoring highly distributed DNS deployments from the outside. We also present recommendations on building a monitoring system that is more reliable and that captures only the relevant metrics.