Re: Reverse DNS and SMTP

["Conrad A. Rockenhaus" <conradr () skyphusion com>]

Patrick Muldoon <doon () inoc net> said:

>       If an ISP who doesn't have reverse DNS setup correctly on their
> mail servers, we point them to the RFC's and generally offer to help
> them correct it.  
>       We have noticed that our spam has reduced drastically, and the
> complaints are few, but alas this is a double edged sword, where if you
> even block 1 legitimate e-mail out of the 100K+ that we receive daily,
> someone is going to complain.   

To be honest, I would do this as a last resort.  For example, if their ISP's 
(or their own, if they have the block delegated) DNS server is misconfigured, 
etc, you might have a issue.  Also, some admins have no clue what reverse dns 
is, seriously :).

I would use a service like MAPS first to see if that resolves the issue, and 
use this as a last resort.

If they don't have an issue with blocking unresolvable ips, then they 
shouldn't have an issue with just using an rbl ;).

--conradr