[ On Friday, June 27, 2003 at 10:06:25 (+0100), Giuliano Gavazzi wrote: ]
> Subject: Re: [Exim] sender verify vs. broken mailer configs, again.
>
> oh, you are so wrong here...! Reverse DNS is not a requirement of
> SMTP, forward DNS is, and his forward DNS is fine.
I never said Reverse DNS was a direct requirement of SMTP.
However correct Reverse DNS is a requirement of the DNS.
SMTP is very tightly intertwined with the DNS and thus correct DNS is na
implicit requirement of fully functioning SMTP.
However since reverse DNS isn't necessary when all else is correct you
have two options: Use Reverse DNS correctly with correct SMTP
configurations, or do not use Reverse DNS at all and hope your SMTP
configuration is correct.
> Sender address
> validity is a requirement
No doubt. I've never said otherwise.
> and not accepting a sender callout attempt
> a foolish act.
No, what's foolish is software which allows an idiot administrator to
mis-configure his system so that a sender callout attempt _must_ fail.
What would be smart would be software which detects when some remote
client tells it that it is mis-configured and that if it is attempting a
sender address verification then it would give up gracefully an inform
its postmaster that there was a local configuration error.
SMTP was not designed with sender callout attempts in question. If not
very carefully implemented they cause deadlock situations. Exim's
sender callout implementation is not careful enough.
--
Greg A. Woods
+1 416 218-0098; <g.a.woods@???>; <woods@???>
Planix, Inc. <woods@???>; VE3TCP; Secrets of the Weird <woods@???>
