[dns-operations] Google DNS overriding TTL settings?

Phil Regnauld regnauld at nsrc.org
Wed Sep 12 21:09:01 UTC 2012


Chris Boyd (cboyd) writes:
> Anyone else seeing this?  Or is it common knowledge I just tripped over?

	You're looking at different RRsets. Google has a cached pair of CNAME
	and A records:

> www.ionadas.com.	9759	IN	CNAME	ionadas.com.
> ionadas.com.		9759	IN	A	208.81.246.21

	While the authoritative server for ionadas.com (ns1.midasnetworks.com)
	presents 

> www.ionadas.com.	3600	IN	A	208.81.246.11

	So I suspect ionadas.com was simply changing from (CNAME -> A) to
	an explicit A record for www.ionadas.com, and you happened to query
	at the right moment.

	The instance of 8.8.8.8 I'm querying is returning the single A record.

	Would have been interesting to compare SOAs as reported by Google and
	the authoritative servers, respectively, to compare serials.

	Cheers,
	Phil



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