How does a DNS server work on a local network?

Question

Domain Name System

Dear admins! I can not fully understand the principle of DNS in the local network. Here the DNS service converts IP addresses to text. This is in the global network, but in the local network it works by the same principle, but what does it transform. For example, I have a network with 20 computers, and 1 server with AD, DNS, DHCP and File roles. Let's say there is access to the Internet, but from our network a request for the DNS service will come from the DNS provider. Or am I guessing wrong. I want to fix the material about DNS.

Answer 1

Indeed, all DNS, both public, provider, and local, perform the same function.
But I would like to clarify, in short, that in your case, the local DNS is used to support AD and resolve names within the domain, which the provider's servers cannot do, simply without having information about the internals of your network. To avoid errors associated with this, stations in the local network should not be assigned a DNS provider.
In other cases, the local DNS may still perform other functions, such as caching.
The workstations, when accessing your DNS, try to resolve the name for the resource. There are two options here: either this is a resource within the domain and it responds to the client, or it is an external resource and you need to contact the upstream server (recursively or directly).
The upstream server can be either a configured forwarder (usually a DNS provider) or a root.
Why does it make sense to configure the ISP's DNS as a forwarder? For the same reason: they can perform some additional functions, such as caching, which will reduce the request time, and geo-references (local CDN nodes of large services, for example).
In general, the structure of the DNS is tree-like and the principles of operation are preserved for higher levels.

Answer 2

The main task of DNS is to convert text names into ip addresses. If an Active Directory domain is not deployed on the local network, then (in most cases) local DNS is optional, you can prescribe external DNS to users, which will be used to determine the IP addresses of servers on the Internet.
When deploying Active Directory, it becomes necessary to deploy a local DNS to store a number of service information. For example, when a computer is added to a domain, the administrator specifies only the domain name, and the operating system receives information about which controllers serve this domain from DNS. You can read more about what AD information is stored in DNS here . (the link is the first one that came across, I have no relation to the resource)

Answer 3

> Let's say there is access to the Internet, but from our network a request for the DNS service will come from the DNS provider. Or am I guessing wrong. I want to fix the material about DNS.
Your local DNS is used to resolve names from ip for your local machines, or vice versa from ip to names. It also acts as a caching DNS for the Internet and redirects to the provider's DNS, if you specified it. Otherwise, it will fulfill the client's requests by itself. This is in short. For more extensive knowledge, I recommend reading the book Bind and DNS. www.books.ru/books/dns-i-bind-5-e-izdanie-552030

Answer 4

All DNS work the same way.
Requests from your network will go to the DNS you set it to.
This could be your local DNS, or your ISP's DNS, or Google's DNS, or even your root DNS.
Usually, the provider's DNS is set as the DNS, but if the provider is against it (and this happens), then you need to either raise your own or use some third-party one.
In the settings of its DNS, they usually attribute the servers where it should send recursive requests. By default, these are root DNS. and IMHO this is correct.
But if this option does not suit you, you can prescribe any other DNS for recursive queries that you like, and which does not mind processing these queries

Answer 5

3-hour DNS video on YouTube:
https://www.youtube.com/watch?v=uF88WlTKy6c