[Sysadmins] DNS....

Colm MacCárthaigh colm at allcosts.net
Wed Jan 6 12:14:29 GMT 2010


On Wed, Jan 6, 2010 at 11:36 AM, Harry Duncan <usr.src.linux at gmail.com> wrote:
> what is the likelyhood of that being accessed when the main site is available or
> do different systems randomly query DNS servers and not necessarily in
> the order they are listed?

It depends on the resolvers; most use a uniform random distribution so
each listed NS record gets an even share of queries. But Bind < 9.3.6
"homes in" on the lowest-latency NS out of the list (it generally
takes about 5 queries for the zone before this happens). As bind is so
prominent a resolver, over time different NSs can get a different
share of queries based on their latency proximity to resolvers.

-- 
Colm



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