[Smaug] question about DNS (was: question about meeting)

cerise@armory.com cerise at armory.com
Wed Jun 15 08:25:58 PDT 2005


On Wed, Jun 15, 2005 at 01:14:54AM -0700, relsqui at armory.com wrote:
> On a semi-tangent, how do domains deeper than three levels work?
> (My school used to be cabrillo.cc.ca.us, although it's cabrillo.edu now.)

   The interesting part of DNS is that it resolves piecewise.  This isn't
exactly how it works, but roughly, speaking, you ask . to resolve .us.  You
ask .us to resolve .ca.  You ask .ca to resolve .cc.  You ask .cc to resolve
.cabrillo.
   The nice part about it is that you don't need some magic box somewhere
to handle arbitrarily huge numbers of domains.  Those little dots partition
the DNS namespace and shuffle out the work for you.  See "DNS for dummies (or
people who really like MS Paint comics)" for more details.
   In essence, all you need to do is put a nameserver at that point which
answers queries.  The only catch is that the step before you needs to know
that you exist.
   Thanks to the magic of caching though, queries rarely go all the way out
to the root servers.
   You may remember from the Armory that spcecdt had control of *.armory.com.
That's because deepthought is registered as the DNS server for armory.com.
Asking for b(oogeyman)?|l(ittlegreenmen)? was as simple as spcecdt entering it
into his DNS configuration.  

-Phil/CERisE




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