[dns-operations] ultradns problems on udns[12].ultradns.net? (amazon.co.uk hard to resolve)

bert hubert bert.hubert at netherlabs.nl
Sat Jun 23 18:17:04 UTC 2007


There's been a small number of problems reported with PowerDNS being unable
to resolve 'www.amazon.co.uk'. 

We first investigated PowerDNS, but it turns out udns[12].ultradns.net are
down right now, or at least severely unavailable from The Netherlands and
other places.

www.amazon.co.uk.: Resolved 'amazon.co.uk.' NS udns1.ultradns.net. to: 204.69.234.1
www.amazon.co.uk.: Trying IP 204.69.234.1, asking 'www.amazon.co.uk.|A'
www.amazon.co.uk.: timeout resolving 

www.amazon.co.uk.: Resolved 'amazon.co.uk.' NS udns2.ultradns.net. to: 204.74.101.1
www.amazon.co.uk.: Trying IP 204.74.101.1, asking 'www.amazon.co.uk.|A'
www.amazon.co.uk.: timeout resolving 

www.amazon.co.uk.: Failed to resolve via any of the 2 offered NS at level 'amazon.co.uk.'
www.amazon.co.uk.: failed (res=-1)

Now I understood that ultradns uses anycast, so I assume this is a rather
large scale DoS effort.

udns[12] sometimes do answer, but never within 500ms.

Just a headsup that if you get complaints about amazon being down, it is not
your fault..

	Bert

-- 
http://www.PowerDNS.com      Open source, database driven DNS Software 
http://netherlabs.nl              Open and Closed source services



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