DNS records NS and A: how to do it right?

Question

Domain Name System

Good evening.
There is a domain example.com from a certain registrar. It has a subdomain subdomain1.example.com. It's done something like this:

subdomain1 A 239.17.239.17

Now we want to add the subdomain2 subdomain, but in such a way that the *.subdomain2 addresses are serviced by a DNS server running at subdomain2.example.com. How to do it right? Now there is such an idea:

subdomain2 A 17.17.17.17
subdomain2 NS subdomain3

Is everything correct or is there a more canonical way?

Answer 1

There are two options,
register 2 records in the parent domain:
subdomain2 IN A 17.17.17.17
subdomain2 IN NS subdomain2.example.com.
and in the subdomain2 zone on subdomain2.example.com everything else is the
second option, apparently, which you need, to register only the
subdomain2 IN NS subdomain2.example.com entry in the parent domain.
and in the zone subdomain2 on subdomain2.example.com
@ A 17.17.17.17
and all the others.
The options are almost equal.