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DNS (Domain Name System) is a hierarchical, distributed, autonomous, reliable database. The first and only of its kind, it offers realtime performance levels to a global audience with global contributors. Every TCP/IP traffic flow including every World Wide Web page view begins with at least one DNS transaction. DNS is, in a word, glorious.

To underline our understanding of what DNS . The Internet economy rewards unlimited creativity in the monetization of human action, and fairly often this takes the form of some kind of intermediation. For DNS, monetized intermediation means lying. The innovators who bring us such monetized intermediation do not call what they sell “lies,” but in this case it walks like a duck and quacks like one, too.

Not all misuses of DNS take the form of lying. Another frequently seen abuse is to treat DNS as a directory system, which it is not. In a directory system one can ask approximate questions and get approximate answers. Think of a printed telephone white pages directory here: users often find what they want in the printed directory not by knowing exactly what the listing is but by starting with a guess or a general idea. DNS has nothing like that: all questions and all answers are exact. But DNS has at least two mechanisms that can be misused to support approximate matching at some considerable cost to everybody else, and a lot of that goes on.

The first widespread form of DNS lie was to treat DNS lookups as mapping requests. CDNs (content distribution networks) such as Akamai and Web optimizer products such as Cisco Distributed Director treat incoming DNS lookups as opportunities to direct the activities of Web browsers. Using the IP source address of a DNS request, these products and services try to guess the proximity of the requester to each of many replicated content servers. Based on the measured load of each content server’s system and network, and on an estimate of each content server’s proximity to that requester, a DNS response is crafted to direct that requester to the closest or best content server for that URI domain.

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