What does the hierarchy in DNS servers look like for a domain name?

Question

Domain Name System

I can't quite figure out the DNS rules in any way.
I have a domain name with a registrar. I register all the records for this domain in
the registrar's panel - A CNAME MX TXT etc. etc.

There is a VPS on which the site files and IPs are indicated in the registrar's records. All DNS records at the registrar lead to this VPS.
I also put a BIND DNS server on this VPS.

The question is, or rather questions.
Is there a seniority in such a hierarchy. For example, I have two identical entries in the domain registrar panel and I have it on VPS (DNS). How it will be processed and whether it will affect each other. Or just what is registered with the domain registrar? Does the rest not matter?

I’m generally confused with these DNS ... You register, wait a day, then it works, then it doesn’t work, then it works and after an hour it doesn’t work ...

Help me figure it out, friends. Or poke your nose into a sensible brief manual to understand the formation. There is no opportunity to master a related specialty. I just want to know and understand. To correctly set up all posts for your site.

Answer 1

For example, I have two identical entries in the domain registrar panel and I have it on VPS (DNS). How it will be processed and whether it will affect each other. Or just what is registered with the domain registrar? Does the rest not matter?

Depends on where the NS record points to, it can point to the registrar's server (most likely it is), or if you changed it and specified your server, then all requests for the zone will fly to it.

You prescribe, you wait a day, then it works, then it doesn’t work, then it works and after an hour it doesn’t work ...

You need to determine which of the servers processes the zone (the registrar or yours), and if changes occur frequently, you can set the TTL for smaller records.
IMHO: As a rule, it is easier (and more reliable if you are not a pro in this) to keep everything on the registrar's servers.
Except when the registrar for some reason does not have support for certain DNS features.

Answer 2

DNS starts with root servers . They have other DNS servers, and others have the following DNS servers. They are registered by adding an NS type record to the DNS settings.

I have a domain name with a registrar. I register all records for this domain in
the panel at the registrar - A CNAME MX TXT etc. etc.

A lot is missing here.
1. Domain name registration. It's just "paper".
2. Someone should add an NS domen.ru record in their DNS - the primary DNS. At the registrar, you specify its IP address. For example, they registered domen.ru on nic.ru, but indicated that the server on reg.ru would be the primary one.
3. Next, you need a secondary DNS server where you will specify the relationship between IP addresses and host machines. The concepts of domain and host are often confused here , which infuriates me a lot. For this, the IP address of the secondary server is registered in the primary DNS. This is where " A CNAME MX TXT etc. etc. " are written. For example, on reg.ru they indicated that the IP address that the home provider allocated will be secondary. Set up a DNS server at home.

Is there a seniority in such a hierarchy.

There is not. But the main thing is to write correctly. If you have added an NS record to your VPS IP address on the primary server. Then requests will (may) go to your BIND. If you registered an NS record in the secondary, this is a mistake. The 3rd level domain -aaa.domen.ru is registered on the secondary server. DO NOT CONFUSE with aaa.domen.ru host!!! A common mistake for many.

Prescribe, wait a day,

Usually you have to wait 4 hours (it used to be so). You can reduce the update time of the DNS zone, if the provider allows)))
Do not forget that DNS requires two IP addresses (two mirror DNS)