different TTLs for multiple TXT records

Matus UHLAR - fantomas uhlar at fantomas.sk
Sat Sep 26 17:56:42 UTC 2020

On 26.09.20 09:58, Verne Britton wrote:
>I see that RFC2181, written I think 20+ years ago, says in part
>>5.2. TTLs of RRs in an RRSet
>>  Resource Records also have a time to live (TTL).  It is possible for
>>  the RRs in an RRSet to have different TTLs.  No uses for this have
>>  been found that cannot be better accomplished in other ways.  This
>>  can, however, cause partial replies (not marked "truncated") from a
>>  caching server, where the TTLs for some but not all the RRs in the
>>  RRSet have expired.
>>  Consequently the use of differing TTLs in an RRSet is hereby
>>  deprecated, the TTLs of all RRs in an RRSet must be the same.

>but in the last few years, perhaps even a decade, TXT record usage has
> expanded to be used for many different and unique purposes, such as domain
> ownership verification and SPF data.

unfortunately, TXT is overloaded with multiple uses. SPF record was
deprecated ... 

>What is the proper avenue to request an enhancement so each TXT record can have its own unique TTL value?

not possible. IF you ask for a TXT, you must get all TXTs, the same for A, NS, MX
and all other records of the same type.

if you don't get something, it means it's not there. This is not just
documented standard - doing it differently would make DNS unreliable.

Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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