Allow Multiple-Cnames in BIND 9

Marc Thach Xuan Ky marc.thach at tesco.net
Sun Dec 2 22:49:51 UTC 2001


Doug,
The working model is of course Cisco Distributed Director.  In its later
incarnations it allows a specifed number of A records to be returned in a
response.  Whether or not this idea is attractive depends on a) money b)
learning to live with the rest of DDs little habits.
rgds
Marc TXK

Doug Barton wrote:

> On Fri, 30 Nov 2001, Jim Reid wrote:
>
> > >>>>> "Bill" == Bill Manning <bmanning at ISI.EDU> writes:
> >
> >     Bill>     bind 9 encourages consistant practice, sometimes w/o
> >     Bill> anything other than "it ought to work this way".  The core
> >     Bill> specs are often vauge, which leads to commentary &
> >     Bill> clarifications.
> >
> > 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.
>
>         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? :)
>
> Doug
> --
>     "We will not tire, we will not falter, and we will not fail."
>         - George W. Bush, President of the United States
>           September 20, 2001
>
>          Do YOU Yahoo!?



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