[Pdns-dev] A & CNAME

Peter van Dijk peter.van.dijk at netherlabs.nl
Wed Jan 4 12:43:28 CET 2012


Hi David,

On Jan 4, 2012, at 12:31 , David Saez wrote:

> Hi
> 
> so, for every request, powerdns does not a CNAME databse lookup and then a A database
> lookup if it did notr find the CNAME record, right ?
> 
> if this is true and your zones contain more A records than CNAME records , then most of
> the CNAME databse lookups are useless (and take valuable resources), for those cases
> it's possible to save those lookups by:
> 
> a) first do the A lookup and the then CNAME lookup
> 
> or
> 
> b) allow hostnames in the A record and when found return a CNAME

For every request, PowerDNS does an ANY database lookup. If there's a CNAME in there, it follows the chain; if there's an A in there, it's done. There are only extra queries *if* the first ANY lookup yields a CNAME. So, PowerDNS already does something better than suggestion (a).

Kind regards,
Peter van Dijk
Netherlabs


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