Re: Outbound email tracking?

Hello Skip,

Thank you for posting in the SBS newsgroup.

Also, many thanks for Javier's great input.

According to your description, I understand that you would like to track
the outbound emails on the SBS Server. If I have misunderstood the problem,
please don't hesitate to let me know.

Javier is right on target, please kindly refer to the suggestions. In
addition, I'm glad to provide the following information for your reference:

1. Enable message tracking, then check the outbound email messages under
Tools->Message Tracking Center. Regarding how to enable Message Tracking,
please refer to the following MS KB article:

246856 XADM: How to Enable Message Tracking in Exchange 2000 Server
http://support.microsoft.com/?id=246856

2. You may refer to the following information to protect Exchange:

A. Disable the Guest account in your SBS 2003 server and enable Stronge
Password Protection. Everytime when you run CEICW you will be asked for
enabling password policies after it ends. I suggest you enable it. You can
also do that in Server Management\Users->Configure Password Policies. For
more information, see:

http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/
security/bpactlck.mspx

B. We can block unsafe attachments in emails by running through CEICW and
enable Internet Email on the wizard. You should see a page named "Remove
E-mail Attachments" where you can choose to block all or some of the unsafe
attachments. For more information, you can search "Remove E-mail
Attachments" (without the quotes) in SBS 2003 Help and Support Center.

C. If you are using SMTP for incoming emails, you can install IMF
(Intelligent Message Filter):

http://www.microsoft.com/downloads/details.aspx?FamilyId=C1B08F7B-8CAF-4147-
B074-8C9C8F277071&displaylang=en

http://www.microsoft.com/technet/prodtechnol/exchange/2003/library/imfdeploy
mspx

However if you are using POP3 Connector for incoming emails, IMF will not
work and you can ignore it.

D. You can block open relay and clean up the SMTP queues by referring to
the following KB article:

324958 How To Block Open SMTP Relaying and Clean Up Exchange Server SMTP
Queues
http://support.microsoft.com/?id=324958

E. You can install third party anti-spam and antivirus software however you
should make sure they are fully compatible with Windows Server 2003 and
Exchange Server 2003. Otherwise they may cause instability to the server.
If you install antivirus software, you should exclude the SYSVOL and
Exchange installation folder exchsrvr from being scanned. For more
information, see:

823166 Overview of Exchange Server 2003 and antivirus software
http://support.microsoft.com/?id=823166

822158 Virus Scanning Recommendations on a Windows 2000 Domain Controller
http://support.microsoft.com/?id=822158

F. (Do NOT use these steps unless you are under this kind of attack)
Nowadays spammers have a new means to avoid filters built into many
systems. They take advantage of a mail systems sending of a non-delivery
report (NDR) when a message cannot be delivered as addressed and returns
the original contents. Since this follows the RFC standard, most all mail
servers will function this way. This is what is called a "Reverse NDR
attack" (RNDR). This form of attack is becoming increasingly widespread.
Some users get it so badly that over 33% of their Internet messages are
attributed to this type of spam. The end result is the spammer has attained
a new form of mail relaying. Your server''s resources are being stolen to
deliver spam.

How does a "Reverse NDR" attack work?

Step 1 Spam email is created with the intended spam victim''s address in
the sender field and a random, fictitious recipient, at your domain, in the
To: field.

Step 2 Your mail server cannot deliver the message and sends an NDR email
back to what appears to be the sender of the original message, the spam
victim.

Step 3 The return email carries the non-delivery report and possibly the
original spam message. Thinking it is email they sent, the spam victim
reads the NDR and the included spam.

What are the symptoms of a RNDR attack?

1. Sluggish email delivery

2. Outbound queues full of non-delivery notices

3. Excessive admin time to clear outbound queues

4. Badmail folder''s size grows quickly

If you are experiencing any of the above, chances are good your mail server
is under attack.

To stop the RNDR from happening, follow the following steps:

To Configure Recipient Filtering

When you enable recipient filtering (if you are using SMTP for incoming
emails) on the SMTP virtual server, e-mail messages that are received from
anyone on the recipient filter are not accepted. Recipient filtering is
set globally, but you enable it on a per-Virtual Server basis on each SMTP
virtual server.

To create a recipient filter:

1. Click "Start", point to "Programs", point to "Microsoft Exchange", and
then click "System Manager".

2. Expand "Global Settings", right-click "Message Delivery", and then click
"Properties".

3. Click the "Recipient Filtering" tab, and then click the checkbox at the
bottom (Filter recipients who are not in the directory).

4. Specify any additional filter options that you want to configure,
Select Apply, and then click "OK".

To enable recipient filtering on the SMTP virtual server:

1. Click "Start", point to "Programs", point to "Microsoft Exchange", and
then click "System Manager".

2. Expand "Servers", expand "<ServerName>", and then expand "Protocols".

3. Expand "SMTP", right-click "Default SMTP Virtual Server", and then click
"Properties".

4. Click the "General" tab, and then click "Advanced".

5. In the "Address" list, click the IP address where you want to apply the
recipient filter, and then click "Edit".

6. Click to select the "Apply Recipient Filter" check box, click "OK", and
then click "OK".

Note: Recipient filter rules apply only to anonymous connections.
Authenticated users and Exchange servers bypass these validations.

If you are using POP3 Connector for incoming emails, you can disable
Exchange from sending NDR emails. See:

294757 How to Control Non-Delivery Reports Using Exchange 2000
http://support.microsoft.com/?id=294757

Best regards,

Nathan Liu (MSFT)
Microsoft CSS Online Newsgroup Support

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