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I just setup a powerdns recursor under a clean Ubuntu 12.04 server. I didn't notice any difference in query times (using dig) so I looked at my /etc/resolv.conf file. I left nameserver= but commented out nameserver= which is my router/dns. Now dig shows a noticeable improvement in query times so all is good.

I only downloaded the recursor, and it seems that I have removed the nameserver address from my server. My question is, how is my server able to resolve names? The recursor.conf file has no external domain setting, and the server doesn't know where any nameserver is so how can dig work at all? Sorry if I am missing something obvious but I am trying to learn more about linux and servers by diving right in.

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This is a guess as I have never used the software so leaving as a comment, maybe it is querying the root name servers itself? – Scott Chamberlain Nov 1 '12 at 5:04
up vote 1 down vote accepted

Recursive DNS server have a built-in list of the IP addresses of all root servers. The rest of DNS descends from the roots.

(If it would forward all queries to another nameserver, it would be called forwarding, not recursive)

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Perfect! I setup the recursor with the intention of using it as a chaching nameserver. I guess that made me think that it was still forwarding but had a memory for the IPs it already resolved. I researched both forwarding and recursing nameservers now and know the difference. I also found out that my recursor was not being used because it was listed after my router in the resolv.conf file. Thanks for the help. – Carson Nov 2 '12 at 2:05

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