DNS delegation based on both location and organization

[Brad Knowles]

At 12:30 AM -0400 2005-09-09, Danny Mayer wrote:

>>>  - I need local resolution and redundancy (I even need load balancers
>>>       for the quickest response time and highest availability)
>
>  You don't really need load balancers for DNS since the architecture of
>  DNS is by its nature distributed. Load Balancers for DNS are a waste of
>  money and effort.

	Regretfully, it's been my experience that PCs will tend to latch 
onto the first IP address that is listed as a resolver for them, and 
they won't ever use anything else -- until they are rebooted, and 
might pick up a different IP.  Those that do actually make use of 
other resolvers that are configured, usually seem to have a 
surprisingly high period of time that they wait for an answer from 
the first one before they roll over to the next one.

	So, if latency is important to your application, or you have any 
of these older PCs around that only ever use the first resolver they 
find, then you really do need load-balancing/high-availability 
switches that you put in front of the caching resolvers, to handle 
fail-over internally, etc....

	At least, this is what I personally saw at AOL, and I've heard 
the same kind of reports from many other admins since then, including 
some relatively recent reports.

-- 
Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.