How does rrset-order work on caching servers?

Mark_Andrews at Mark_Andrews at
Wed Oct 2 23:34:11 UTC 2002

> In a previous thread (mailing.unix.bind-users, DNS name resolution
> question, 9/12/02) Kevin Darcy <kcd at> wrote:
> > Now, if you want to always return the A records in a particular *order*;
> > that may be a little trickier. Because of caching complications, you'd
> > have to configure *all* servers which may be answering that query --
> > regardless of whether they are authoritative or merely caching servers --
> > with an "rrset-order" option, or the non-BIND equivalent. If some of
> > those servers are not in your control, or are non-BIND implementations
> > which lack an equivalent feature, this may end up not being feasible.
> How does rrset-order work on caching servers?  I understand that when
> the answers are taken from the zone file the order of records in the
> file will be honored.  Does this imply that on the caching servers the
> order of the answers in a response packet will be honored when the
> records are stored in the cache, and then they will be returned in
> that order as well?  Any tricks or gotchas?
> I have an intranet deployment where I may be able to control all the
> BIND servers, but for now I can't access them for testing this.  I
> apologize if this is documented somewhere - I haven't found it yet.
> thanks,
> -andrew
	Caches apply their own rules to the ordering of responses they
	hand out.  This may or may not reflect the order the records were
	received in.

Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at

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