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I have Ubuntu 12.04 with BIND9, working just as a caching server (forwarding to 8.8.8.8).

When I use, for example, dig +norecurse @l.root-servers.net www.uniroma1.it, I obtain the following output:

; <<>> DiG 9.8.1-P1 <<>> +norecurse @l.root-servers.net www.uniroma1.it
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

Using Wireshark I discovered that the outgoing queries are correct, but there aren't any incoming answers. Why?

P.S. Using simply dig www.uniroma1.it I obtain the correct answers.

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1 Answer 1

up vote 0 down vote accepted

This is an issue with how the root name servers respond(or fail, in this case) to queries than with the dig tool itself.

The following queries to a secondary DNS server in Italy will respond appropriately:

  • dig +norecurse @dns.nic.it www.uniroma1.it

    as will a query to one of Google's DNS servers using this:

  • dig +norecurse @8.8.8.8 www.uniroma1.it

Off the top of my head, I don't recall how the Primary DNS servers are set up in regards to individual queries. It may be a security, or DDOS avoidance measure, but I would just be guessing at this point. Hope this helps.

Update: See the second comment in response to this question which gives a much better explanation of interpreting a response from the top level name servers using the dig tool.

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