On 8/15/2014 9:08 PM, Linda A. Walsh wrote:
I was wondering if anyone had any experience in showing their ISP "the
light"...
Oh well....
Linda, is your email domain tlinx.org? I'm assuming that it is because
there is an under construction web page on that domain and I cannot
imagine a commercial ISP putting an under construction web page on a
domain they own.
Anyway, getting back to the technical aspects of your problem,
I'm gonna assume that for whatever reason (maybe your out in the boonies
and are still on a dialup) that you cannot simply setup a Linux box
behind a broadband connection and use some provider like dydns.org (or
whatever they are calling themselves now) and accept your own
email.
And because of that your forced to use a commercial mailserver then
fetch mail from that.
If that is the case, I am suspecting that you are PERHAPS confusing
what is called the "envelope" address with the "header" address in
the incoming email.
The envelope address is passed during the SMTP handshake. That is
almost certainly being checked for validity by your ISP and it is
passing.
The header address is supplied during the DATA phase and as such
it is part of the mail message content. In general, you cannot filter
on this during the SMTP handshake since it isn't supplied until the
mailserver already has agreed to accept the message.
Instead it must be filtered during the content filtering phase, after
the mail has been accepted.
I do understand that from a user's POV it is very confusing to see a
message in your inbox that says From: fakeaddress@fakedomain but
if you actually looked at the full header of the email, you would
see the REAL and legitimate from address (assuming your ISP has
turned on the feature that displays the envelope address used by
the SMTP sender in the header)
For example here is the header fragment of your post that is in MY mailbox:
Return-Path: <users-return-104656-tedm=ipinc....@spamassassin.apache.org>
Received: from mail.apache.org (hermes.apache.org [140.211.11.3])
by mail.ipinc.net (8.14.7/8.14.7) with SMTP id s7G49cin016427
for <t...@ipinc.net>; Fri, 15 Aug 2014 21:09:38 -0700 (PDT)
(envelope-from
users-return-104656-tedm=ipinc....@spamassassin.apache.org)
Received: (qmail 23944 invoked by uid 500); 16 Aug 2014 04:09:29 -0000
Mailing-List: contact users-h...@spamassassin.apache.org; run by ezmlm
Precedence: bulk
list-help: <mailto:users-h...@spamassassin.apache.org>
list-unsubscribe: <mailto:users-unsubscr...@spamassassin.apache.org>
List-Post: <mailto:users@spamassassin.apache.org>
List-Id: <users.spamassassin.apache.org>
Delivered-To: mailing list users@spamassassin.apache.org
.
.
.
Received-SPF: unknown ipv4:173.164.175.65 (athena.apache.org:
encountered unrecognized mechanism during SPF processing of domain of
sa-u...@tlinx.org)
Received: from [173.164.175.65] (HELO Ishtar.hs.tlinx.org) (173.164.175.65)
by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 16 Aug 2014 04:09:23
+0000
Received: from [192.168.4.12] (athenae [192.168.4.12])
by Ishtar.hs.tlinx.org (8.14.7/8.14.4/SuSE Linux 0.8) with ESMTP id
s7G48ufp053787
for <users@spamassassin.apache.org>; Fri, 15 Aug 2014 21:09:00 -0700
Message-ID: <53eed954.50...@tlinx.org>
Date: Fri, 15 Aug 2014 21:08:52 -0700
From: "Linda A. Walsh" <sa-u...@tlinx.org>
User-Agent: Thunderbird
Please notice something:
Envelope sender address:
users-return-104656-tedm=ipinc....@spamassassin.apache.org
Header sender address:
"Linda A. Walsh" <sa-u...@tlinx.org>
The mail message was accepted because the envelope-from address of
users-return-blah blah blah was valid, not because the sa-u...@tlinx.org
address was valid.
iN the typical spam message, the envelope sender is valid, the header
sender is not.
Spammers do it this way because of sender-ID, domainkeys, and
software like milter-callback - all of which checks the envelope
email address for validity. They do not want emails sent back
to their real address (that is used in the envelope) which was checked
for validity, they want emails sent back to the fake address (so the
emails don't actually reach them)
I hope that explains to you why you erroneously think your ISP is
accepting fake emails. In other words, to put it politely, you don't
know what your talking about and need education that I have just
supplied.
Assuming now your properly humbled, and still reading, the good news
about all of this is that assuming your ISP is NOT doing ANY KIND of
content filtering, that you can post-process your incoming email using
SpamAssassin on your own system, and get the same results you would
get if your ISP was running SpamAssassin on the mailserver. SA looks at
the header address and takes into account whether the From: address is
bogus or not.
You haven't posted what operating system your using to read mail with
or any of that, so I cannot advise you how you would go about running
SpamAssassin on whatever your using to script all your incoming email
with.
Now, as for your question on "showing the light":
You have not posted what your paying (if anything) or any financial
details of your arrangement with this ISP so I will merely quote 2
business maxims:
1) You get what you pay for, generally. With a few exceptions (like the
mattress industry, the used car industry)
2) A customer's ability to affect the decisions of a business they buy
product from is directly proportional to their profitability compared
to other customers of that business.
In simple terms, if your paying $1000 a month for product from this
ISP that is costing them $10 a month, and every other one of their
customers is paying $10 a month, then you say "jump" and they will ask
"how high"
But if you are paying $10 a month for product from this ISP for product
that is costing them $10 a month, and every
other one of their customers is paying $1000 a month, when you say
"jump" then your gonna hear crickets chirping.
I regularly have to remind "customers" of mine who are 503(c) charities
of this who are getting reduced cost product as a result of some deal
a prior charity member negotiated. I still chuckle in recalling a
highly indignant letter from one of those bozos a couple years ago
telling us he was moving his charities "business" elsewhere as he didn't
think we were responsive enough in returning his phone calls - his
charity was paying us $0 a month. (as in, nothing) I actually took the
trouble to respond to him and expressed my overwhelming thanks for his
leaving, as the cessation of his free service would immediately raise
the profitability of my business.
I'm not sure he ever made the connection but oh well.
Personally I would evaluate your mail provider based on stuff like
uptime, and not worry too much about if his spam filtering is crappy
or not. Given a choice your far better off with a mail provider that
reaches 99.9999% uptime and doesn't lose mail, but has crappy spam
filtering, then a provider that is going down all the time and has
great spam filtering. The fact of the matter today is that the only
kind of spam filtering that really works well anymore is content
filtering, the spammers have figured out ways around all the other
systems.
Ted
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