Many A-records
Barry Margolin
barmar at alum.mit.edu
Thu Apr 8 19:21:47 UTC 2004
In article <c540ko$25n7$1 at sf1.isc.org>,
Jonathan de Boyne Pollard <J.deBoynePollard at Tesco.NET> wrote:
> JL> Every time you create a CNAME where you could have used an A
> JL> record you create a situation where every resolver looking
> JL> for your service must do two lookups instead of one.
>
> BM> Unless the server is authoritative for both the CNAME record
> BM> and its target. In that case the server will return both
> BM> records, [...]
>
> If the first client-side aliase leads out of the server's bailiwick, then
> the resolving proxy DNS server _still_ needs to perform further lookups,
> because the second alias in the chain will be discarded as poison.
Yes. That's not what I was talking about -- I specifically said "if the
server is authoritative for both the CNAME record and its target." This
isn't an uncommon configuration, e.g. for things like:
@ IN A 1.2.3.4
www IN CNAME @
so that the web site can be referred to as either <domain> or
www.<domain>.
--
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
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