The following is the response from ipal.net to an ordinary email sent
from punsterproductions.com (my own server); I include the headers from
the message as well, for completeness. It was obviously rejected
because the admin at mx0.ipal.net implemented a "reverse DNS" check, and
the resulting hostname did not match. I've been making the point for
some time that this is not a great idea, as one will block legitimate
email, because there are so many people who are STUCK, without any
recourse, with ISPs that refuse to properly delegate IP address blocks
(they instead provide "dummy" host names for reverse lookups). My own
so-called "business" DSL service (from Covad, the only DSL provider in
my area) is such a case. Until I can afford a T1 line from a "real"
ISP, I am stuck with this situation. (Don't think I haven't tried to
explain this to Covad. I might as well beat my head on a brick wall.)
All I can do is ask MTA admins to not reject email just because the
reverse DNS hostname doesn't match. In a lot of perfectly legitimate
cases, it will not match. There are plenty of other (better) ways to
block spam, without blocking legitimate email traffic.
Jim Roberts
Punster Productions, Inc.
*** begin sample ***
This message was created automatically by mail delivery software (Exim).
A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
phil-stunnel-users@???
SMTP error from remote mailer after RCPT
TO:<phil-stunnel-users@???>:
host mx0.ipal.net [209.102.192.90]: 550
<h-64-105-159-234.PHLAPAFG.covad.net[64.105.159.234]>:
Client host rejected: mail from domains with generic/dialup/DHCP
addresses is not accepted - contact your ISP for support
------ This is a copy of the message, including all the headers. ------
Return-path: <punster@???>
Received: from [64.105.159.238] (helo=puns04)
by puns01.punsterproductions.com with asmtp (TLSv1:RC4-MD5:128)
(Exim 4.02)
id 18KpIr-00076F-00; Sat, 07 Dec 2002 19:28:14 -0500
Message-ID: <00ec01c29e50$b1f39c60$04fea8c0@localnet>
Reply-To: "James P. Roberts" <punster@???>
From: "James P. Roberts" <punster@???>
To: "Phil Howard" <phil-stunnel-users@???>,
<stunnel-users@???>
References: <20021207012756.A1044@???>
<Pine.LNX.4.33L2.0212062354250.9903-100000@???>
<20021207025722.A2126@???>
Subject: Re: POP/IMAP then STUNNEL->SMTP
Date: Sat, 7 Dec 2002 19:28:10 -0500
Organization: Punster Productions, Inc.
MIME-Version: 1.0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2800.1106
X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106
*** end sample ***
