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There must be something wrong with my understanding of DNS and since I might not be the only one I would like to ask this here for clarification.

If I make a whois on google.com I realize that its name servers are:

Name Server: NS1.GOOGLE.COM
Name Server: NS2.GOOGLE.COM
Name Server: NS3.GOOGLE.COM
Name Server: NS4.GOOGLE.COM

At this point I am confused because these DNS depend on the domain itself.

And if I do

    dig google.com @ns1.google.com
or: dig ns1.google.com @ns1.google.com

The response does show aa flags proving that ns1.google.com is indeed the Authoritative server for everything about google.com.

How is this possible? This seems to me like the chicken and egg problem.

If I want to know the NS servers of google.com I ask a root server for the .com TLD, correct? It tells me that ns1.google.com is that NS server. Now I need to resolve ns1.google.com but it depends on the domain that I was trying to resolve in the first place... so I'm stuck in a loop!

The only explanation I can think of is that the root server hosts a zone for google.com and is therefore able to return an IP for ns1.google.com. But what is this service that allows us (or only big players?) to have some zone hosted by the root servers? (I'm probably assuming wrong here but I can't see another explanation)

I noticed pinterest.com is set up the same way.

FlorianB
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  • You already find out those are glud records involved (but your question is offtopic). You can easily see them if you query the parent authoritative nameservers: `dig ns1.google.com A @a.gtld-servers.net`. For anyone thinking about using this setup: yes it works, it can have merit in some cases, but it also have drawbacks. It is better not to do that until you understand the DNS well. – Patrick Mevzek Oct 24 '19 at 14:47

1 Answers1

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Ah, someone on Freenode gave me the keyword I needed: GLUE RECORDS (which is not a music label).

A very good explanation is provided here: https://serverfault.com/questions/309622/what-is-a-glue-record

FlorianB
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