How to determine source of spam?

I have a 2000 Microsoft small business server running Exchange 2000 with latest patches.  There are about 30 clients.  I am seeing spam messages in the outbound queues and am unable to determine the origin.  Relaying is off and 25 is closed except from our filtering service, so the problem is most likely internal.  Short of powering off all the computer and turning them back on one by one, does anyone have a suggestion?
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Look at the Email headers for clues.
rjccazAuthor Commented:
Is there a way to view the headers directly from Exchange?  Keep in mind that I don't know which (or IF a) client is causing the messages, so cannot open the messages from Outlook.

David Scott, MCSENetwork AdministratorCommented:
Yes, double click the queue (smtp connector i'm assuming) and then click find now and it will show all the messages in the queue.  double click one of the messages and it will show you the header
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rjccazAuthor Commented:
Ah-ha!  We might be on to something...  I got an error, says "Enumerate messages from the queue node"

After enumerating the messages, it appears that all these messages are from  "postmaster@(MY_DOMAIN).com

Still unsure as to the original source and what to do about them...  Any ideas?
David Scott, MCSENetwork AdministratorCommented:
its probably ndrs from your postmaster account from spammers doing "directory harvesting" they send to endless combos of and when the program doesn't get an ndr it knows it a vaild email address then it starts sending spam to it.

to stop this.  you have to check an option to "filter recipient not in the directory"  

go to ESM, global settings, right click message delivery, properties, recipient filtering, put a check in "filter recipients who are not in the directory" this will block emails that are sent to that doesn't have a mailbox.  Your server won't send an ndr, just will block it and force their server to do the ndr.
rjccazAuthor Commented:
I would agree, but I see no option for this, probably because this is Exchange 2000.  Not only that, but the initial symptom was a returned email warning that spam may be being generated on our network and it was more than just an NDR.  This original notification was sent from an AOL account and included the following:

Return-Path: <>
Received: from ( []) by (v120.9) with ESMTP id MAILINMA053-8b04735f1a735e; Sat, 10 Nov 2007 13:00:13 -0400
Received: from server.(MY_DOMAIN).local ((MY_ISP)]) by (v120.9) with ESMTP id MAILRELAYINMA062-8b04735f1a735e; Sat, 10 Nov 2007 13:00:08 -0400
Received: from User ([]) by server.(MY_DOMAIN).local with Microsoft SMTPSVC(5.0.2195.6713);
Fri, 9 Nov 2007 13:05:22 -0700
Reply-To: <>
From: "PayPal"<>
Subject: Receipt for Your Payment
Date: Fri, 9 Nov 2007 12:54:44 -0700
MIME-Version: 1.0
Content-Type: text/html;
Content-Transfer-Encoding: 7bit
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2600.0000
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000
Message-ID: <SERVERyuqr60g1XbIv10000045a@server.(MY_DOMAIN).local>
X-OriginalArrivalTime: 09 Nov 2007 20:05:22.0368 (UTC) FILETIME=[DC0F9400:01C8230B]
X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_822_from :
There is no recipient filtering in Exchange 2000. If you are under that kind of attack you will have to go third party. Vamsoft ORF can do recipient filtering it will also do the tar pit which you need as well.

David Scott, MCSENetwork AdministratorCommented:
i wish there different zones for sbs 2000 and 2003 and exchange 2000 and 2003.  

Why? The information is in the original question that it was SBS 2000.

David Scott, MCSENetwork AdministratorCommented:
b/c if there were separate zones for the different versions i would not be looking at questions in sbs 2000 or exchange 2000.  

i mean there is different zones for windows 2000, xp, 2003, etc

why not exchange and sbs?  
rjccazAuthor Commented:
Well, I believe I have found the issue.  Appearantly, these are all NDR's.  I had considered that possibility, but was thrown by the fact that they were still appearing.  I have read that it is normal for the NDR messages to continue to appear for upto 48 hours after the initial problem is resolved.  For now, I think my problem is solved.  Thanks for all who helped! for Exchange 2003 for Exchange 2000 or 2003
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