[dns-operations] cloudflare-dns.com doesn't have reverse DNS

[Joe Abley]

Op 23 sep 2023 om 19:48 heeft Fred Morris <m3047 at m3047.net> het volgende geschreven:

> I think what's happening with cloudflare-dns reflects my working hypothesis, which is that infrastructury stuff has a higher likelihood of having reverse DNS attended to and cloudy, direct to consumer stuff has a lower likelihood.

I guess, maybe, depending on what you mean by infrastructury and consumer, which are pretty broad categories :-)

> The question in my mind is how often the same entity controls the forward domains and the relevant reverse domains, because there is little to no technical impediment in that case for generating and publishing a notional-as-to-intent reverse DNS entry from their own forward emissions.

Using Cloudflare's customers as an example, some people bring their own addresses for a variety of reasons and others use Cloudflare addresses.

In both cases it is possible for there to be a one to one, static mapping between a single name and a single address, but the more common situation by far is for there to be many (sometimes very, very many) names associated with a single address, and for the mapping to be dynamic and to change often. What reverse DNS strategy makes sense in that scenario? The strategy of not provisioning reverse DNS at all in those cases does not seem ridiculous. 

In the case where a one to one mapping does exist between a customer address and a customer name, my observation is that people don't bother to make reverse DNS available even though it is quite easy to do so. This seems to support the apparent consensus that there's no compelling operational reason to bother.


Joe