Lots of CNAME's

[David Botham]

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bind-users-bounce at isc.org wrote on 02/27/2004 06:18:21 AM:

> Dear All,
> 
> Is there anyone out there who has DNS records containing many many 
CNAME's?
> 
> We are thinking of creating host records in our DNS system which 
potentially
> will have around 1000 CNAME's attached. I need to make sure this will 
not
> have an effect on performance of DNS etc.. Eg. If you're trying to 
resolve a
> CNAME to an IP address which, in the record has tons of other CNAME's, 
will
> this slow the response down and affect performance?

You should not have a problem attributable to the CNAME RR's.  Even if you 
do have 1000's of CNAME's for a given A RR, when someone looks up one of 
the CNAME's, one additional query will be required to get the A RR. 

On the other hand, if you "chain" them together, you could start to see 
problems.  Where you have to lookup one CNAME, only to get another CNAME, 
which yeilds another query to possibly get another CNAME.  Well, I think 
you can see where that can go in a hurry.  Not to mention the posibility 
of loops.


Dave...


> 
> Regards
> 
> Matt
> 
> 
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