DNS ROOT understanding

Jim Reid jim at rfc1035.com
Sat Nov 13 08:48:54 UTC 2004

>>>>> "Jonathan" == Jonathan de Boyne Pollard <J.deBoynePollard at Tesco.NET> writes:

    JR> [...] if your name server is well-behaved, it will only
    JR> communicate with a root server 4 or 5 times a week: every time
    JR> it queries for a domain name in a TLD that hasn't been cached
    JR> already.

    Jonathan> Wrong.  It will also communicate with a root server once
    Jonathan> each for _every individual_ domain name looked up that
    Jonathan> isn't under one of its delegated TLDs (which will
    Jonathan> include a wide range of things from the ever-popular
    Jonathan> "localhost.localdomain." to single-label "AAAA" lookups
    Jonathan> generated by the broken search path mechanism in
    Jonathan> IPv6-aware GLIBC), and will cache the resultant negative
    Jonathan> responses for at most 24 hours (and so, given its
    Jonathan> popularity, will probably ask a root server about
    Jonathan> "localhost.localdomain." at least once per day).

Read what I said. The circumstances you describe are not those of a
well behaved DNS setup.

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