default local DNS caching name server
h.reindl at thelounge.net
Sat Apr 12 11:37:25 UTC 2014
Am 12.04.2014 13:25, schrieb William Brown:
>>> Consider, I get home, and open my laptop. Cache is cleared,
>>> and I'm now populating that cache with the contents from the ISP.
>> No, why contents from ISP? Local resolver will populate cache from root servers, no?
> This isn't how DNS works ..... You populate your cache from the ISP, who
> queries above them and so on up to the root server.
no - only if you enter your ISP's servers as forwarder which
makes only partial sense because it lowers the effective TTL
and you have more and more cahcings between the origin and
your machine while some of them may ignore TTL at all
a DNS server doing recursion don't ask any forwarder
nice, but you need to understand the contents especially
point 3 and because point 1-8 it is called "recursion"
because you sart to ask the root-servers which tell you
"hey i don't konw the address, but i know who knows .com"
followed by the server for .com answers "well, i don't
know the answer but i can tell you who knows"
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