[dns-operations] asking the European a-k.cctld.us servers for MX records

Chris Thompson cet1 at cam.ac.uk
Tue Mar 26 12:07:09 UTC 2013

On Mar 26 2013, Thomas Mieslinger wrote:

>am I the only one having trouble to resolve MX records for .us Domains?
>When doing a dig MX soderman.us @a.cctld.us in Europe  I get no answer 
>at all.
>In the US I get a referral to the nameservers which are authoritative 
>for this domain. To make this even more strange dig AAAA soderman.us 
>@a.cctld.us or any other record type except for MX just gives the 
>referral also in Europe.
>Can you just try it yourself?

>From the UK (Cambridge) I see the same effect on all IPv4 addresses
for the US nameservers


They time out specifically on MX queries, whether RD is set or not.

On the other hand, the IPv6 addresses

  b.cctld.us. 2001:503:d1ae:ffff:ffff:ffff:ffff:ff7e
  f.cctld.us. 2001:500:3682::11
  k.cctld.us. 2001:503:e239::3:1

work fine.

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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