[dns-operations] A record round-robin behavior

Brad Knowles brad at stop.mail-abuse.org
Wed Apr 19 17:02:05 UTC 2006

At 11:31 PM -1000 2006-04-18, Mark K. Pettit wrote:

>  that the very first query for "foo" to your server would return the
>  records in the order ".4, .5, .6".  Then the very next query for "foo"
>  would return the records in the order ".5, .6, .4".  Then ".6, .4, .5".
>    Then it would start over again.

	IIRC, that's the way it used to work with BIND-4 and maybe early 
versions of BIND-8.

>  The behavior I actually observe seems completely random.  I do get
>  records in the order I expect (e.g. no ".6, .5, .4"), but it appears to
>  be random which will be listed first.

	I believe that this is an accurate description of current 
behaviour with BIND-9.  Since the standard doesn't say anything about 
order, the implementors first decided to use a deterministic 
algorithm and then later decided that a (pseudo) random algorithm was 

	I prefer the pseudo-random algorithm, myself.

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

  LOPSA member since December 2005.  See <http://www.lopsa.org/>.

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