MX record ordering

Brad Knowles brad.knowles at Skynet.be
Fri Mar 30 18:21:31 UTC 2001


At 12:54 PM -0500 3/30/01, lawrence.a.kravets at us.arthurandersen.com wrote:

>  We have recently upgrade to Bind 9.1.0 from Bind 4.9.3. Given the
>  following, we have reason to believe that the order of response of the
>  following has changed. We expect that it would split equally between server1
>  and server2. Unfortunately we see more traffic on server1 than server2.
>  Has something changed in Bind 9?
>
>  mailhosts      IN   MX   10   server1.zone.com.
>  mailhosts      IN   MX   10   server2.zone.com.
>  mailhosts      IN   MX   20   server3.zone.com.
>  mailhosts      IN   MX   30   server4.zone.com.

	In theory, you are right.  The load should be balanced across the 
first two machines.  In practice, there are still plenty of sites out 
there for whom their local nameserver doesn't properly round-robin 
records once they have been cached, so you will see a traffic 
imbalance.

	The only way around this problem is to put something like a layer 
4 load-balancing switch in front of the machines which can all 
perform the same function, and to get this kind of information out of 
the DNS entirely.

	Sorry, guy.  Don't mean to burst your bubble, but this is just 
one of the many little weirdnesses about the DNS and Internet e-mail.

-- 
Brad Knowles, <brad.knowles at skynet.be>

/*        efdtt.c  Author:  Charles M. Hannum <root at ihack.net>          */
/*       Represented as 1045 digit prime number by Phil Carmody         */
/*     Prime as DNS cname chain by Roy Arends and Walter Belgers        */
/*                                                                      */
/*     Usage is:  cat title-key scrambled.vob | efdtt >clear.vob        */
/*   where title-key = "153 2 8 105 225" or other similar 5-byte key    */

dig decss.friet.org|perl -ne'if(/^x/){s/[x.]//g;print pack(H124,$_)}'


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