[dns-operations] Blackhole IANA question

Chris Thompson cet1 at cam.ac.uk
Thu Aug 5 13:39:43 UTC 2010

On Aug 5 2010, Jeroen Massar wrote:

>You do realize that the point of a blackhole server is to literally
>blackhole the traffic? ;)

They aren't meant to "blackhole" the traffic in the sense of not replying.
They give authoritative NXDOMAIN responses in the hope that they will be

If Alberto is getting timeouts, it may be because some intermediate
router is discarding traffic to AS112. (JANET used to do this, which
always seemed to me to be counter-productive.) Try using traceroute
to blackhole-{1,2},iana.org and see if that reveals anything.

>Please read http://en.wikipedia.org/wiki/AS112 and/or
>http://public.as112.net/ for more details why it is not "normal" to send
>these queries.

Certainly, it's always better for recursive nameservers to respond
locally (negatively or positively, as the case may be) to reverse
queries for RFC1918 addresses.

Chris Thompson               University of Cambridge Computing Service,
Email: cet1 at ucs.cam.ac.uk    New Museums Site, Cambridge CB2 3QH,
Phone: +44 1223 334715       United Kingdom.

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