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Let's say I own example.com, that I bought by ExampleRegistrar.
Let's say that, by default, this registrar uses their own nameservers ns1.exampleregistrar.com, ns2.exampleregistrar.com.

Thus, when a client wants to browse to www.example.com, it probably goes like this:

  • root DNS servers looks for .com nameserver
  • .com nameserver looks for example.com, it sees ns1.exampleregistrar.com and passes the request to this nameserver
  • ns1.exampleregistrar.com looks for www.example.com and finally finds IP 203.0.113.5 which it gives to the client.

Question: how does it work if I configure a custom nameserver ns1.othernameserver.com in the registrar domain's settings?

Does this mean the registry for .com will directly have ns1.othernameserver.com in its database?

Is it correct that, then, any request from a client to www.example.com will never go through any of the registrar's servers?

Basj
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1 Answers1

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The registrar essentially just deals with sales and customer interactions, they are not part of the actual live operations from a DNS perspective.
Well, not as part of their role as a registrar, anyway. It's very common that registrar companies also provide DNS hosting services for customer zones, but that is just a case of value-add or upsell of non-registrar services to their customers.

From a registry as well as DNS operational perspective there is no difference functionally if you used registrar-provided nameservers, third party nameservers, your own nameservers, or any mix of these.

In all these cases, the registrar just sends the set of NS records that the registrant has selected (maybe implicitly if you choose to use their DNS hosting services) to the registry and those are published in the TLD zone.

Håkan Lindqvist
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  • Thanks! Just to be sure to understand, let's take `stackoverflow.com` as an example. It seems that their first nameserver is `NS-1033.AWSDNS-01.ORG`. Is this a correct way to see the path: first using one of the 13 root servers: `dig @198.41.0.4 stackoverflow.com` => this gives us nameservers for `com.` (registry?), for example `a.gtld-servers.net.` i.e. `192.5.6.30`. Then we can do `dig @192.5.6.30 stackoverflow.com` and then we see the 4 nameservers, including `ns-1033.awsdns-01.org.`. Is that correct? – Basj Mar 24 '21 at 08:52
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    @Basj Yes, something like `dig @a.root-servers.net stackoverflow.com`, `dig @a.gtld-servers.net stackoverflow.com`, `dig @ns-1033.awsdns-01.org stackoverflow.com` would be a valid example of manually reproducing the lookup steps. – Håkan Lindqvist Mar 24 '21 at 08:58
  • Last thing @HåkanLindqvist: how does the registrar "send" the information *"Dear TLD .com registry, please now use `ns.anothernameserver.com` as nameserver for the domain `example.com` - we are the official registar for `example.com`, proof: XYZ."*, what's the name of this process / automated API, out of curiosity? I'd like to understand how a registrar proves to the registry that they are authorized to do this, and how they ask to update the registry database. – Basj Mar 24 '21 at 09:15
  • @Basj It varies, but often EPP. See https://serverfault.com/questions/688837/how-do-registrars-register-authoritative-name-servers-with-root-name-servers/689852#689852 – Håkan Lindqvist Mar 24 '21 at 11:55