[dns-wg] [Ext] Re: Changes to Time-to-Live (TTL) values in reverse DNS zones

On 4/21/22, 1:46 PM, "Dave Lawrence" <tale at dd.org> wrote:

>    Edward Lewis writes:
>    > I once did some work [that could not be made public] where I began
>    > to suspect that the two were unrelated. 
>
>    Unrelated, or just less correlated than you might otherwise imagine?

Unrelated.

I'd studied an event which made it apparent that resolvers vastly ignored the long TTLs in play.  At the time I learned that two popular strains of resolver code had an "internal" limit on the TTL they would accept [which is old news now], meaning any authoritative server operator who was banking on long TTLs to lower traffic was not going to realize any benefit.

And, in the case of the event, it meant that the event had a far greater impact that it should have.  Adhering to the TTL, most resolvers would have "stepped over" the problem (in time) and not noticed.  But because many came back pre-TTL-maturely, they stepped into the event.

Ever since then I've questioned the conventional wisdom that TTL and query rate were inversely related - as advertised.  It seems that time-to-re	query is determined more by the resolver's design than the authoritative server's setting of the TTL.