Where in the DNS process are NS records used?

Question

I register a new domain, mynewdomain.com, at a hosting company.

In the advanced DNS settings there is an A record which maps mynewdomain.com to a ip address.

In my webhost control panel, it shows me the nameservers for the domain: ns1.mywebhost.net & ns2.mywebhost.net

When I type in mynewdomain.com into a browser and hit enter I believe the following happens.

1. ISP resolver searches "." nameserver
2. ISP resolver then told to search ".com" nameserver instead.
3. ISP resolver finds mynewdomain.com, and searches the zone file to get the A record.

So my question is, where does my webhost's nameservers come into play? I believe the flaw in my logic comes from the fact that my zone file (in which the A record is kept) is stored on ns1.mywebhost.net). But if that is the case, how does my ISP resolver know to look here? (because I didn't type this into my address bar)

Answer 1

Amongst other things, it tells the primary who it should send update notifications to when the zonefile is updated (strictly, when the serial number is bumped).

Edit: this has nothing to do with your 1,2,3 sequence above. Recursive resolution doesn't use the NS records; instead it uses the glue records. You can find more about those on Wikipedia, or in this answer .