Malcolm Weir wrote:
> 
> It seemed a reasonable conclusion because the guy was complaining about
> having an "incorrectly set" RDNS, when that's a manifestly not the case.

Ray was talking about someone else.  Whether that person's PTR was 
actually incorrect is unknown and irrelevant. :)

> Indeed.  Asking isn't too high a bar.  However, as it happens, the vendorS
> (there are two involved here) have declined.  They observed that there's no
> meaning to the reverse DNS, and (as I have pointed out) these days forward
> and reverse DNS frequently don't match anyway.

I wouldn't have said anything at all, except that I thought I'd clarify 
that the plugin that he's using doesn't check for matching PTR and A 
records in DNS.

Beyond that, when you say "forward and reverse" frequently don't match, 
I think you're confused about what happens with PTR matching lookups. 
I'm not aware of any software or services that do an A (or AAAA) lookup 
and then check the PTR to see if it matches.  Clearly, this would rarely 
be the case and not very useful.  It could also only be done on 
*outgoing* connections, not on connections accepted by a server (like 
Ray's).  Instead, some servers will do a PTR lookup on the IP address 
that established the connection that they've accepted, and then do an A 
or AAAA lookup on that name to see if it matches.  This will virtually 
always be the case, and many programs consider it a serious problem if 
they don't.

If your PTR doesn't match the A or AAAA, you're probably trying to forge 
your identity.


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