5 out of 7 .io nameservers appear to be down

Re:5 out of 7 .io nameservers appear to be down by lewisheadden on Thursday July 02, 2015 @09:04AM (#9818528)

They actually seem to work fine but you have to set the non-recursive bit.

  $ dig ns io @b.nic.ac +short

  ; <<>> DiG 9.8.3-P1 <<>> ns io @b.nic.ac +short
  ;; global options: +cmd
  ;; connection timed out; no servers could be reached
  $ dig ns io @b.nic.ac +short +norec
  b.ns13.net.
  [... extracted for brevity]
  ns3.icb.co.uk.

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Re:5 out of 7 .io nameservers appear to be down by kijeda on Thursday July 02, 2015 @09:41AM (#9818743)

This is the correct answer. The monitoring tool is sending the wrong kind of DNS queries to these servers, and these servers are filtering them out. You can argue the servers should at least respond with an error, however they are functioning correctly when you ask them for an authoritative response (i.e. a delegation)

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Re:5 out of 7 .io nameservers appear to be down by sajal83 on Thursday July 02, 2015 @09:56AM (#9818860)

(monitoring tool author here) Agree. Makes sense. We should have run this test with RD bit unset.

But .. IIRC if RD is set when quering a non-recursive, it should respond normally with authoritative response Recursion Available (RA) flag unset. It does not mean it should drop the query totally.

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Re:5 out of 7 .io nameservers appear to be down by jamiesonbecker on Thursday July 02, 2015 @02:06PM (#9820551)

Dropping bad queries is often a DDoS countermeasure.

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Re:5 out of 7 .io nameservers appear to be down by skion on Thursday July 02, 2015 @09:54AM (#9818849)

This is indeed a typical configuration for authoritative name servers.

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