[dns-operations] Why would an MTA issue an ANY query instead of an MX query?

Paul Vixie paul at redbarn.org
Sun Jun 10 14:23:30 UTC 2012

On 2012-06-10 12:59 PM, Patrick W. Gilmore wrote:
>>> A single ANY query for a domain gives you the NS, MX, TXT and SPF
>>> records, plus any A/AAAA record present. At scale, who knows, the
>>> reduction in number of queries probably adds up.
>> It strikes me as laziness and cost-shifting.
> If you need to do multiple queries (e.g. TXT & MX), is it better for
> either side to do two queries instead of one?

yes, since the queries can be transmitted simultaneously, and there's
way less risk of TC=1 and followup TCP.


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