Allow Multiple-Cnames in BIND 9

[Doug Barton]

On Fri, 30 Nov 2001, Joseph S D Yao wrote:

> On Fri, Nov 30, 2001 at 05:50:46PM -0800, Doug Barton wrote:
> >
> > On Fri, 30 Nov 2001, Jim Reid wrote:
> ...
> > > That's as may be. But RFC1034 could hardly be any clearer about
> > > multiple CNAMEs:
> > >
> > >     If a CNAME RR is present at a node, no other data should be present
> >
> > 	And the traditional response to your traditional response is that
> > a second CNAME doesn't constitute "other data," since it's the same RR
> > type. Whether that's true or not is open to debate, but there are some of
> > us who don't think it's cut and dry.
>
> Then how about RFC 2181, "Clarifications to the DNS Specification."?

	"... and then I say," Well that RFC is still standards track. Like
I said, this argument has been going on forever, and there aren't any hard
cold, unambivalent standards that please everyone.

> > 	To try and lead the conversation down a more productive route, we
> > occasionally get complaints from end users who are stuck behind really
> > old/broken resolvers that don't handle the truncated bit properly, thereby
> > preventing them from resolving addresses for hosts whose A RR set is too
> > large to fit into a UDP packet. One thing we've considered is patching
> > BIND to always return some random subset of the possible A records that
> > will fit into a UDP packet... any comments on the pro's or con's of that
> > approach? Does anyone have a working model that I could crib from? :)
>
> Ideally, one might upgrade the resolver.  ;-)

	Wish I could, but we don't have access to the resolvers for every
ISP our customers come from. The only thing we have control over is what
we send, so that's where we have to work.

-- 
    "We will not tire, we will not falter, and we will not fail."
	- George W. Bush, President of the United States
          September 20, 2001

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