How does rrset-order work on caching servers?

[Mark_Andrews at isc.org]

> 
> In a previous thread (mailing.unix.bind-users, DNS name resolution
> question, 9/12/02) Kevin Darcy <kcd at daimlerchrysler.com> 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
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org