Deep Dive into NTP Pool Popularity and Mapping

Abstract

Time synchronization is crucial on the Internet, and the Network Time Protocol
(NTP) serves as the primary synchronization protocol. The NTP Pool, a
volunteer-driven project introduced 20 years ago, connects clients with NTP servers. Our analysis of Root DNS queries reveals the NTP Pool's widespread use as the most popular time service. Despite its popularity, there has been limited scrutiny of how NTP servers are assigned to clients. In this paper, we investigate the NTP Pool's DNS component (GeoDNS), which maps clients to servers, and find that the current algorithm is overly strict, creating unnecessary risks. We have shared our findings with the NTP Pool operators, who acknowledge them and plan to revise their algorithm to enhance security.