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I am trying to understand something about DNS that seems too simple but I could not find anything related to this in particular.

When I buy a domain name (example.com) I specify DNS servers with the registrar (ns1,ns2.example.com). When someone is looking to resolve anything related to example.com, I presume that at the registrar level, they are directed to the Nameservers I specified with the registrar.

My question is, if the primary nameserver I were to put down was ns1.example.com (at my purchased domain), how does anything resolve, as that seems like it puts any request in to a recursive loop back to itself? I did not notice anywhere actually having to put in an IP address (other then on my nameserver which - how did the request get there in the first place)

Where am I going wrong with my reasoning?

Thanks.

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2 Answers 2

My question is, if the primary nameserver I were to put down was ns1.example.com (at my purchased domain), how does anything resolve,

This works because you must provide your registrar is called a glue record. Basically you must provide the IP address for your name servers in addition to the names.

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Thanks for this quick reply. I figured it would work something like that, thing is, I have done registrations with multiple registrars, and don't recall ever giving an IP address. –  yayim Oct 7 '09 at 5:18
    
Then you've presumably never given an in-zone name as a nameserver -- or your recollection is faulty. –  womble Oct 7 '09 at 6:14
    
faq.domainmonster.com/dns/glue_record describes it using example.com, just as you have asked above. –  Scott Lundberg Oct 7 '09 at 13:18

This concept of glue records is so fundamental to DNS that I recommend you do some Googling of that term and get a solid understanding of it.

If you've never had to specify the IP address of a DNS server it is no doubt because you were using an established DNS server, perhaps belonging to your registrar or hosting company, and they already have the glue record in place.

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