Configuring different TTLs in multiple RRs for the same domain name, TYPE, and CLASS

Ray Bellis ray at isc.org
Thu Mar 24 16:22:05 UTC 2016


On 24/03/2016 16:18, Ben Bridges wrote:
> TXT records are multiple-purpose.  They can be used for SPF records,
> Office 365 “MS” records, DMARC records, or whatever arbitrary uses
> someone dreams up, all for the same domain name.  Microsoft wants a
> short TTL for their Office 365 records, but I would prefer to generally
> use a longer TTL for most records (including other TXT records) in order
> to reduce the query load on our servers.  It would be nice to be able to
> set a short TTL for the Office 365 record but a longer TTL for other TXT
> records for the same domain name.

OK, I can see why you'd want that, but it's yet another reason why
overloading TXT records for multiple purposes was (and remains) a bad
idea :(

As explained by RFC 2181, an RRset is supposed to be indivisible, and
"bad things happen" if some parts of an RRset expire before others.

Ray




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