Email with no sender? Any hints what this is and how to treat it?

[ovizii]

I got this mail today, which slipped through EFA with a score of 3.05

the only headers are:

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address	no watermark or sender

The original message headers:

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X-Greylist: delayed 00:05:26 by SQLgrey-1.8.0
Received: from mail.rosenpartners.com.au (mail.rosenpartners.com.au [110.174.132.21])
     (using TLSv1 with cipher AES128-SHA (128/128 bits))
     (No client certificate requested)
     by jacob.ict-consult.co.za (Postfix) with ESMTPS id 16DF3100103
     for <HunterGrover8487@intramed-distribution.co.za>; Mon, 16 May 2016 14:44:03 +0200 (CEST)
MIME-Version: 1.0
From: <postmaster@rosenpartners.local>
To: <HunterGrover8487@intramed-distribution.co.za>
Date: Mon, 16 May 2016 22:38:31 +1000
Content-Type: multipart/report; report-type=delivery-status;
     boundary="ddd5d552-15b9-4c79-9445-8294316e466a"
Content-Language: en-US
Message-ID: <d8487f63-2576-4bdd-92dd-3b1f55e1a1ce>
In-Reply-To: <2f6e9d929ce85afa3af442dbe9251eff@intramed-distribution.co.za>
References: <2f6e9d929ce85afa3af442dbe9251eff@intramed-distribution.co.za>
Subject: Undeliverable: Re:

- my EFA is responsible for domain intramed-distribution.co.za
- the email address HunterGrover8487@intramed-distribution.co.za doesn't exist though

[ovizii]

I found this thread: viewtopic.php?t=993

Do I understand my options correctly, that if I don'T use EFA as outgoing email server I should simply set:

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Treat Invalid Watermarks With No Sender as Spam = high-scoring spam

but if EFA starts marking DSNs from my internal mailserver as SPAM I should set it to 2?

[ovizii]

OK, this is becoming irritating and I need some help to sort it out.

These mails are now bein autolearned as HAM by EFA:

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Spamassassin Autolearn:	 Y  (not spam)

and slip through to a non-existent recipient which obviously bounces back.

The ones that are marked as spammy generate an email to the recipient with the link to release them, which then bounces back to my postmaster account :-/

[shawniverson]

I am not a fan of watermarking. It is unreliable at best. You are at the mercy of remote servers to preserve the watermark in the header on reply.

I would suggest disabling it altogether or setting it to a low score (such as 2).

Many legit emails, such as bounces, may not have a sender defined.

As for your non-existent receipients, have you considered setting up a receipient list in postfix? Basically, anyone not in the list gets rejected and the emails are dropped.

I am also not a fan of the release email link and it is now deprecated due to a major bug. I also recommend disabling this feature. Work is in progress in the MailWatch project to allow this feature using MailWatch standard reports instead.

[ovizii]

Thanks for the advice, I'll read up on watermarking some more.

Regarding bounces, I have implemented a "safe" usage of backscatterer.org => http://www.backscatterer.org/?target=usage and am watching it...

Recipient lists are a no-go as the mail server I am forwarding to, is running ISPCFG3 a free web hosting control panel where I manage my email users and its not integrated with EFA so I would be doing double work.

Can you give me a link to read more on what is going to replace the release email link solution? That is the sole reason I switched from scrollout to EFA in the first place