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Leon
Asked: 2016-04-20 18:24:47 +0800 CST

DNS - how does it resolve the name servers itself? [duplicate]

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Domain name: abc.com Name Server: ns1.abc.com and ns2.abc.com

I am running a DNS server and hosting the zone (abc.com) on-premise.

When a client wants to resolve *.abc.com, it will query ns1.abc.com or ns2.abc.com, that is straight forward.

The question is how does it resolve ns1.abc.com before it can sends query to it?

domain-name-system nameserver resolve

3 Answers

  1. To find the name server for abc.com a DNS server will query the DNS server for com. This will return the nameserver information provided to your registrar. You must provide the IP addresses to the registrar when the servers are within your domain.

    To find the com DNS servers the DNS server will contact one of the root domain servers. When the DNS server starts it will use a hints file to do an initial lookup of the root servers.

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  2. you assign DNS servers on clients when configuring IP, so each client already have the ip addresses of DNS servers. and on your DNS servers there are NS records for your name servers.

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  3. You should never specify a name server by name, only by IP. So you wouldn't tell the DNS client to talk to ns1.abc.com, you'd tell the client to talk to it's ns1.abc.com's IP.

    For the top level DNS servers, a "hints" file is, or used to be, used to tell the client of the top level DNS servers.

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