[dns-operations] Trustworthiness of PTR record targets

Doug Barton dougb at dougbarton.us
Tue Mar 4 17:48:03 UTC 2014

Ignoring that Jim's response was a bit snarky, and also ignoring the 
other responses you've already received, it's hard to answer your 
question without knowing a bit more about what you're up to. However, in 

1. Anyone can put anything in a PTR record. There is no safe assumption 
that the content is accurate.

2. In my experience (which is not thorough, but also not zero) anti-spam 
folks are completely uninterested in what's in the PTR, and generally do 
not do any blacklisting by domain name in the sense you seem to mean.



On 03/03/2014 09:26 AM, Stephen Malone wrote:
> Hi Folks,
> For PTR records out there that are pointing to domains other than those
> that you control, I’m looking to understand common practice around their
> setup. Two questions:
> 1.In general, can I trust PTR records? Is ownership of the target domain
> validated at setup time by ISPs, and if yes, how is this done?
> 2.If ownership of PTR targets is not routinely validated, is there a
> risk that the target domain could be blacklisted by anti-spam providers?

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