Debugging Triplicate Emails

[Ashley Aitken]

Hello All,

I'm still trying to debug why one colleague (at least, others may not  
be telling me) always receives triplicate emails from me, and not  
others who use our same mail server etc.

He does use MS Outlook for his mail but he doesn't have this problem  
with anyone else, so it seems to implicate me, and particularly my  
machine.

Interestingly, others (his partner) on the same email server that he  
uses doesn't seem to get triplicates from me  either, so it seems  
very strange (at least to me).

I believe I "configured" postfix in the past to try to send using  
localhost (for when I was travelling) by following advice from the  
Web but I get lost when I look in the postfix config files now.

I'm using the latest version of MacOSX Server as our mail server and  
it seems to work fine for other users (no triplicates as I  
mentioned).    I'm running the latest version of MacOSX Client.

For example, I can send emails to another email server at work, or to  
my gmail account, or to other friends and they don't seem to receive  
triplicate emails.

I sent a test email to my colleague from within our local network  
whilst logging for SMTP was set to Information and got the following  
(slightly anonymised):


> Apr  8 20:39:11 server postfix/smtpd[13688]: connect from  
> server.ourdomain.com[1.2.3.4]
> Apr  8 20:39:11 server postfix/smtpd[13688]: B6879DA5341:  
> client=server.ourdomain.com[1.2.3.4], sasl_method=XYZ,  
> sasl_username=ashley
> Apr  8 20:39:11 server postfix/cleanup[13670]: B6879DA5341: message- 
> id=<0FCD9333-7D02-4BED-86D1-E55319394CFD at ourdomain.com>
> Apr  8 20:39:11 server postfix/qmgr[13650]: B6879DA5341:  
> from=<ashley at ourdomain.com>, size=660, nrcpt=1 (queue active)
> Apr  8 20:39:39 server postfix/smtpd[13911]: connect from localhost 
> [127.0.0.1]
> Apr  8 20:39:39 server postfix/smtpd[13911]: 95A4CDA5384:  
> client=localhost[127.0.0.1]
> Apr  8 20:39:39 server postfix/cleanup[13670]: 95A4CDA5384: message- 
> id=<0FCD9333-7D02-4BED-86D1-E55319394CFD at ourdomain.com>
> Apr  8 20:39:39 server postfix/qmgr[13650]: 95A4CDA5384:  
> from=<ashley at ourdomain.com>, size=1271, nrcpt=1 (queue active)
> Apr  8 20:39:39 server postfix/smtpd[13911]: disconnect from  
> localhost[127.0.0.1]
> Apr  8 20:39:39 server postfix/smtp[13690]: B6879DA5341:  
> to=<fabio at theirdomain.com.au>, relay=127.0.0.1[127.0.0.1],  
> delay=28, status=sent (250 2.6.0 Ok, id=13124-10, from MTA: 250 Ok:  
> queued as 95A4CDA5384)
> Apr  8 20:39:39 server postfix/qmgr[13650]: B6879DA5341: removed
> Apr  8 20:39:40 server postfix/smtp[13927]: 95A4CDA5384:  
> to=<fabio at theirdomain.com.au>, relay=theirdomain.com.au[2.3.4.5],  
> delay=1, status=sent (250 OK id=1HaWfi-0003NQ-Qr)
> Apr  8 20:39:40 server postfix/qmgr[13650]: 95A4CDA5384: removed
> Apr  8 20:40:12 server postfix/smtpd[13688]: disconnect from  
> server.ourdomain.com[1.2.3.4]


If I try to analyse that:

> Apr  8 20:39:11 server postfix/smtpd[13688]: connect from  
> server.ourdomain.com[1.2.3.4]
> Apr  8 20:39:11 server postfix/smtpd[13688]: B6879DA5341:  
> client=server.ourdomain.com[1.2.3.4], sasl_method=XYZ,  
> sasl_username=ashley

I am not connecting from the server but I believe it is suggesting  
this because our external IP address resolves to server.ourdomain.com?

> Apr  8 20:39:11 server postfix/cleanup[13670]: B6879DA5341: message- 
> id=<0FCD9333-7D02-4BED-86D1-E55319394CFD at ourdomain.com>
> Apr  8 20:39:11 server postfix/qmgr[13650]: B6879DA5341:  
> from=<ashley at ourdomain.com>, size=660, nrcpt=1 (queue active)

Ok, so it gets the message to send correctly.

> Apr  8 20:39:39 server postfix/smtpd[13911]: connect from localhost 
> [127.0.0.1]
> Apr  8 20:39:39 server postfix/smtpd[13911]: 95A4CDA5384:  
> client=localhost[127.0.0.1]

This looks ominous, another connection from my machine (localhost?)

> Apr  8 20:39:39 server postfix/cleanup[13670]: 95A4CDA5384: message- 
> id=<0FCD9333-7D02-4BED-86D1-E55319394CFD at ourdomain.com>
> Apr  8 20:39:39 server postfix/qmgr[13650]: 95A4CDA5384:  
> from=<ashley at ourdomain.com>, size=1271, nrcpt=1 (queue active)

Hmmm, message id is the same but size is double, more headers?

> Apr  8 20:39:39 server postfix/smtpd[13911]: disconnect from  
> localhost[127.0.0.1]

Disconnect from local host ok.

> Apr  8 20:39:39 server postfix/smtp[13690]: B6879DA5341:  
> to=<fabio at theirdomain.com.au>, relay=127.0.0.1[127.0.0.1],  
> delay=28, status=sent (250 2.6.0 Ok, id=13124-10, from MTA: 250 Ok:  
> queued as 95A4CDA5384)
> Apr  8 20:39:39 server postfix/qmgr[13650]: B6879DA5341: removed

Sending once?

> Apr  8 20:39:40 server postfix/smtp[13927]: 95A4CDA5384:  
> to=<fabio at theirdomain.com.au>, relay=theirdomain.com.au[2.3.4.5],  
> delay=1, status=sent (250 OK id=1HaWfi-0003NQ-Qr)
> Apr  8 20:39:40 server postfix/qmgr[13650]: 95A4CDA5384: removed
> Apr  8 20:40:12 server postfix/smtpd[13688]: disconnect from  
> server.ourdomain.com[1.2.3.4]

Sending twice?  It looks like it is, one initiated from the server  
and one from my localhost?

But they get three copies?

I've asked them to bounce the emails to me and the headers are  
exactly the same on all the emails.  I'm wondering if some email  
client or some receiving email servers are smart enough to ignore  
triplicate emails but this one isn't?

If anyone can suggest what may be wrong from the information provided  
I would be most grateful, or any other places I should be looking,  
things to do etc.

Cheers,
Ashley.


--
Ashley Aitken
Perth, Western Australia
mrhatken at mac dot com
Skype Name: MrHatken (GMT + 8 Hours!)