Name Servers 1

[ice78991]

Just a general question. If I type in a a web address in to my browser, say

http://www.example.com

is it true to say that the browser checks the root nameserver for an ip address which gives the location of the nameserver where the zone file exists for

http://www.example.com.

So when for example you register a domain name and change the nameserver settings through your registrar , are you changing the entry in the root name server and are you pointing it to another name server with your zone file?

 

[gdvissch]

FYI there is a DNS forum at Tek-tips that might answer some of your questions...

In fact DNS is very hierarchical and the root servers are actually the final dot in in a fully qualified domain name.
so the FQDN of your example is "

http://www.example.com."

with the final "." indicating that this is a fully qualified name.

so your client PC talks to the root servers to find a dns server with an authority over the ".com" domain (other servers manage .uk, .org, .net .biz etc...

Then your client talks the new dns server it just received from the top level one, and will ask who is responsible for "example.com". If you registrar has registered this name for you, the .com server will have an entry for example.com pointing to the registrars dns server.

The client now talks to the registrars dns server to find out who has

http://www.example.com.

This could be on the registrars dns server, but if you have a lot of servers, you could have your own dns server. In this case, you registrar's dns server will have an entry for your dns servers in it list. Every thing under example.com would the be forwarded to your own dns. The other possiility is to have an entrry for every public name in "your" domain in their server. It's clear that if you have a lot of servers and many name or address changes, you want to manage this yourself. In the other case, the registrar will do if for you (if you pay them of course)

CU
G.

 

[pansophic]

Actually your client only talks to the DNS servers listed in their configuration files (ipconfig or /etc/resolv.conf). Each DNS server in the request chain will either respond with the ip address if they are the Start of Authority (SOA) or have cached the name, or they will request the information from the DNS server(s) in their configuration.

At some point (this part is unclear to me, but I believe that it is based on the number of times that the request has been pushed up to the next server in the hierarchy) a request is made to a root server for the SOA record (lists the nameserver(s) associated with a domain). That nameserver then requestst the hostname from the nameserver(s) from the SOA record and pushes that response back down the chain.

If you perform a packet capture from your client, even for a name that doesn't exist, you won't see a direct request to any root server.

But all of that said, whenever you change the DNS servers for your domain, an updated SOA record is pushed to each of the root servers.


pansophic

 

[ice78991]

Thanks - Continuing in DNS Forum