----- Original Message ----
> From: Frank Cusack <fcus...@fcusack.com>
> To: postfix-users@postfix.org
> Sent: Sun, January 17, 2010 8:26:15 PM
> Subject: Re: How to not reject valid MTAs for inconsistent forward/reverse
> DNS.
>
> On January 12, 2010 1:33:46 PM -0500 Victor Duchovni
> wrote:
> > Don't use "reject_unknown_client_hostname" indiscriminantly.
>
> Ironically, enough time has passed that I now received a bounce from
> Stan, due to my smtp host not having a PTR record. (It was a 450 and
> finally my smtp server gave up.)
>
> What is the reason for rejecting mail based on PTR records *at all*?
> It clearly doesn't confirm whether an MTA is valid* or not.
>
> -frank
> * not that I'm even sure what the definition of "valid" is.
Frank,
A proper ISP and Host would have the proper PTR Records set up thus validating
the said sender as being part of a reputable ISP or Host. Most of the spammers
I have come across have improper DNS Records set up meaning no name lookup
based on IP address e.g 127.0.0.1 returns nothing. So rejecting email email by
PTR Records is a spam prevention thing.
At least this is my opinion.
Thanks
Daniel Reinhardt
Website: www.cryptodan.com
Email: crypto...@yahoo.com
Junior Network Security Engineer
