So if i only used iterative requests to a recursive dns server and since this server has cached results from recursive queries, does this mean the iterative request gets a result from the cache or just a response with a difference server to check?

Example for clarification:

User requests example.com recursive dns server doesn't have it so fetches and saves the ip in cache iterative request made to this server does the response return the cached result or just another server ip?

  • $\begingroup$ This does not seem to be a computer science question. Community votes, please! $\endgroup$ – Raphael Nov 4 '15 at 19:59
  • $\begingroup$ @Raphael, this is about how the Internet works. Part of CS in my book, and not off-topic until there is RFC.SE or some such... $\endgroup$ – vonbrand Nov 5 '15 at 1:32
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    $\begingroup$ @vonbrand The existence of other SE sites is utterly irrelevant to our scope, either way. $\endgroup$ – Raphael Nov 5 '15 at 7:06
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    $\begingroup$ Please try to use full sentences. Your example for clarification is a stream of words with no punctuation, which is unnecessarily difficult to read. It should be split into a sequence of sentences. I recommend that you edit that part of the question to use full sentences, punctuation, and capitalization. $\endgroup$ – D.W. Nov 5 '15 at 7:51

Cached data about a domain for which a DNS server is not authoritative could only have come from prior recursive queries. If you send a query without the RD (recursion desired) bit set, the server is not going to send you any of the cached recursive data that it has. If the server is authoritative for the domain you asked about then it will answer authoritatively, otherwise the answer section of the response will be empty.


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