Root server list

[Kevin Darcy]

Andrey G. Sergeev (AKA Andris) wrote:
> Hello Scott,
>
>
> Wed, 13 Aug 2008 14:07:08 -0700 Scott Baker wrote:
>
>   
>> If I run dig without any options it outputs a list of root servers:
>>
>> ;; ANSWER SECTION:
>> .                       482765  IN      NS      K.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      E.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      L.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      M.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      J.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      H.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      I.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      F.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      G.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      B.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      A.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      C.ROOT-SERVERS.NET.
>> .                       482765  IN      NS      D.ROOT-SERVERS.NET.
>>
>> Where does that information come from?
>>     
>
> This data come from the server's cache which is initialized at the 
> server startup using the named.root file (the hints). This file acts as 
> a source of the names and IP addresses of the name servers holding the 
> copy of "." (the root zone).
>
>   
It's necessary to understand the concept of "priming". The hints file is 
used as a source of, well, hints, about where to get the *real* 
root-zone information. When the nameserver starts up, it uses the hints 
to talk to a real root nameserver, gets the real root-zone information, 
and then never uses the hints again (except perhaps if all of the root 
records expire simultaneously?).

While it's true that you only need 1 working entry in "hints" to prime 
and start running, it's safer and more efficient to periodically keep 
the file up to date, as root server addresses change.

                                                                         
                                                - Kevin