bind and multiple a records

Chuck Swiger cswiger at
Sun Apr 23 16:21:00 UTC 2006

Chad Leigh -- Shire.Net LLC wrote:
> On FreeBSD 6.0 with bind9, if I define a host to have multiple A 
> records, such that some IP addresses are listed more than once, for 
> example:
[ ... ]
> Will those addresses listed more than once show up more often as the 
> "answer" to name server requests (or more often as the first address 
> since it lists all addresses in response alternating the order)??

The last I'd heard, BIND implemented multiple-RR round-robin'ing but not 
relative weighting if a RR is specified several times.

Note that you're probably never going to achieve fine-grained control by using 
DNS load-balancing anyway, since client-side caching behavior is more 
significant than what your side does.

If you actually need load-balancing to do something, you're better off 
implementing it between a front-end DTS box (an Alteon or something like that if 
need be) and a bunch of back-end servers which actually implement meaningful 
load-balancing based on the workload of your back-end servers...


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