The Domain Name System (DNS) is a critical component of the Internet

infrastructure. It allows users to interact with Web sites using

human-readable names and provides a foundation for transparent

client request distribution among servers in Web platforms, such as

content delivery networks. In this paper, we present methodologies

for efficiently discovering the complex client-side DNS infrastructure.

We further develop measurement techniques for isolating the

behavior of the distinct actors in the infrastructure. Using these

strategies, we study various aspects of the client-side DNS infrastructure

and its behavior with respect to caching, both in aggregate

and separately for different actors.