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DNS performance and the effectiveness of caching

The Domain Name System (DNS) is an essential part of the Internet infrastructure and most Internet applications depend on the correct operation of DNS prior to establishing a connection to a remote host. We seek to understand the client-perceived performance and behavior of DNS and investigate the effectiveness of its caching mechanisms. Our goal is to identify the factors that affect DNS response latency, the errors and failure modes of DNS, and its scalability. An analysis of the effectiveness of DNS caching is especially important in light of several recent changes in the way DNS is used. Content distribution networks (CDNs) and popular Web sites with multiple servers are increasingly using DNS as a level of indirection to help balance load across servers, provide fault tolerance, or to direct each client request to a topologically nearby server.