How to diagnose short-term failures on the DNS server (reg.ru)?

Question

Domain Name System

Hello!
Some time ago, we started receiving complaints from some of our clients that our site is sometimes unavailable, while we do not see any problems on our part - everything works fine. Clients who contact us on this problem use completely different providers, live in different cities.
After a session in teamviewer, it was found that the domain could not be resolved:
ping: cannot resolve consultsystems.ru: Unknown host
Usually it is enough to wait a bit and the domain is restored. Also, everything starts working if we register our domains in hosts directly on the client's computer. But this cannot be called a normal solution to the problem.
We suspect that reg.ru DNS servers sometimes don't return records for our domain. Contacted those several times. reg.ru support, but the answer is the same: "At the moment everything is working - come back when it won't work." Arguments that failures are extremely selective and short-lived were not heard.
Has anyone encountered a similar problem? What means can be used to trace these DNS errors in order to still present them to reg.ru?

Answer 1

Not necessarily a problem in reg.ru. Between clients and their servers there is a recursor - for example, a provider or Google.
Are you monitoring the site? Add a script by type to your monitoring:

dig @ns1.reg.ru consultsystems.ru
dig @ns2.reg.ru consultsystems.ru

Or use the trial period of some saas a la https://www.uptrends.com

Answer 2

It's very easy to diagnose: don't use their crappy dns, because if you use them, you will have problems.
Take dns from yandex or cloudflare, they are free.