[dns-operations] OT: NXDOMAIN / public resolvers and zen.spamhaus.org

[Rod Rasmussen]

Actually I think the issue is that Spamhaus purposely does not provide resolution for major public open resolvers.  I can double check with them, but I believe they don't want people (i.e. bad guys) using those resolvers to walk their entire block list, and of course, they have a business model to support, and for major e-mail handlers, they have a fee structure.  If you're using a resolver like Google's, then they can't tell who's really hitting their servers for RBL requests and why.

Cheers,

Rod

On Mar 27, 2011, at 11:56 PM, Stephane Bortzmeyer wrote:

> On Sun, Mar 27, 2011 at 03:22:39PM -0500,
> Lyle Giese <lyle at lcrcomputer.net> wrote 
> a message of 45 lines which said:
> 
>> I have also seen it mentioned that using these public resolvers are
>> not appropriate for use with mail servers as they may give out
>> answers for non-existent domains.  They want to push requests for
>> non-existent domains to a custom page for their ad or special search
>> pages.
> 
> This is *not* a property of "public DNS resiolvers" in general. This
> is a property of some systems (OpenDNS, for instance) but, others
> clearly stated they won't lie:
> 
> http://code.google.com/speed/public-dns/faq.html#nxdomains
> 
> The mentioned document
> <http://www.spamhaus.org/faq/answers.lasso?section=DNSBL%20Usage#261>
> (which carries the same claim) is badly wrong.
> 
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