Messages passing through Mailscanner lose X-Mailer headers, and turn up as SPAM, but no Mailscanner no problem

[John Van Ostrand]

On Mon, 2006-11-13 at 16:42 -0500, Leah Cunningham wrote:
> I have a strange problem.  I have a client whose internal user is able to 
> successfully send messages to me from their old Q-Mail server without a 
> problem. If the same user, with the same mail client, computer, etc, sends a 
> message through a newer mail server that I have set up for them that runs 
> MailScanner (with Postfix), the message is detected by my own mail server 
> (and many others) as Spam, and has different headers.  It seems part of the 
> reason is that Spamassassin thinks it is a bogus Outlook, maybe because the 
> X-Mailer header is not there.  
> 
> The major difference I notice is that in the one that went through 
> MailScanner, we are missing these two headers that are in the one that went 
> through their old mail server, and I want to know why:
> 
> X-Mailer: Microsoft Outlook, Build 10.0.2627
> Importance: Normal
> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180

This may not be much help, but you have received headers missing too.
Based on the Spam report in the second message I think you've identified
the missing Outlook headers as being the key. Find out whether postfix
or Mailscanner is removing them and you should be fine.

I would try a tcpdump on the client's postfix server to see what is
being delivered to postfix. Do a similar one on the outgoing email to at
least confirm that it's the client server.

I use sendmail, where a split queue is used. One may be able to examine
the queue files in each queue if you can stop the processes at the right
time.

Good luck.

-- 
John Van Ostrand                       Net Direct Inc.
CTO, co-CEO                   564 Weber St. N. Unit 12
                                  Waterloo, ON N2L 5C6
john at netdirect.ca                     ph: 518-883-1172 x5102
Linux Solutions / IBM Hardware        fx: 519-883-8533