Re: DNS goofups galore...

["H. Peter Anvin" <hpa@transmeta.com>]

"Michael H. Warfield" wrote:
> 
> On Thu, Feb 08, 2001 at 02:58:30PM -0800, H. Peter Anvin wrote:
> > Followup to:  <Pine.LNX.4.10.10102081346001.16513-100000@innerfire.net>
> > By author:    Gerhard Mack <gmack@innerfire.net>
> > In newsgroup: linux.dev.kernel
> > >
> > > Thanklfully bind 9 barfs if you even try this sort of thing.
> > >
> 
> > Personally I find it puzzling what's wrong with MX -> CNAME at all; it
> > seems like a useful setup without the pitfalls that either NS -> CNAME
> > or CNAME -> CNAME can cause (NS -> CNAME can trivially result in
> > irreducible situations; CNAME -> CNAME would require a link maximum
> > count which could result in obscure breakage.)
> 
>         It generally forces another DNS lookup.  If you do a resolve on
> a name of type=ANY it returns any MX records and A records.  If you then
> do a resolve on the MX records, you then get a CNAME and then have to
> add an additional lookup for the CNAME.  If you have a lot of MX records
> and not all the servers are "up" that can add up to a significant
> increase in DNS traffic.
> 

Wouldn't that be true for any CNAME anyway?

	-hpa

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