[Pdns-dev] Strange answer in pdns_recursor

bert hubert bert.hubert at netherlabs.nl
Fri Apr 29 08:52:04 CEST 2011


On Thu, Apr 28, 2011 at 07:33:39PM -0300, José Arthur Benetasso Villanova wrote:
> Hi all.
> 
> I've compiled last svn head and I'm getting this:
> 
> $ dig +noall +answer @localhost -p 5301 production.cf.rubygems.org
> production.cf.rubygems.org. 3600 IN     CNAME
> d2chzxaqi4y7f8.cloudfront.net.
> .                       3600    IN      SOA     ns1.dnsimple.com.

You get this on the very first query, on next queries you will get a
'normal' answer.

One of the nameservers authoritative for the chain leading from
production.cf.rubygems.org thinks it is authoritative for the root, and it
should not be thinking that.

Check out:
$ dig production.cf.rubygems.org @ns2.dnsimple.com

DNS resolution could simply stop there as this is an idiotic answer. This is
happening more and more however, as the state of DNS continues to degrade
and everybody expects this to work.

> Does anyone have seen this before?

Yes, more and more nameservers are serving seriously damaged answers.

I've now changed svn head to it fully ignores such weird SOA answers, and
the measurements are now running on how this impacts the DNS resolution of
the top 1 million domains names.

	Bert


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