IMF 2 in Exchange 2003 SP2

IMF or Intelligent Message Filter is a free spam filtering software that comes with Microsoft Exchange 2003 SP2. However, if you've never had to install IMF before or if you've been forced to remove its predacesor (version 1 was a separate download) you may notice that IMF is not automatically enabled. If you're finding your mailbox as a great solution for finding a date, cheap watch, college diploma, discount software and pharmaceuticals... consider enabling IMF.

Note: IMF operates as an event sink of the SMTP protocol and protects your SMTP server from being flooded with SPAM. If you are downloading your mail from your ISP by the means of POP3 connector, these messages will bypass IMF and get delivered straight into your inbox. This is done by design and there is no (clean) way of implementing IMF to protect this mail without third party tools.

Warning: Since writing these articles I have received thousands of messages from you and here are two most frequent problems:

1. IMF stops working because IMF v1 was not removed prior to the SP2 installation. This is a bug and Microsoft has been notified. Normal operation of the Exchange 2003 SP2 is to detect IMF v1 and crash if found - asking you to remove it. Under certain circumstances, IMF v1 is not detected (but is installed) and the setup continues eventually breaking IMF. While it does not excuse the fact that people experiencing this problem obviously did not read the release notes, it is a bug nonetheless and I hope there is a fix soon. After all, it is much easier to fix software than stupid system administrators.

2. IMF does not scan messages bigger than 3 Mb. This is by design, if your message has huge attachments it will not be scanned for spam content by IMF or SmartScreen content filters.


Enabling IMF v2 in Exchange 2003 SP2

While Exchange 2003 SP2 installs IMF by default, it does not automatically enable it. First, lets make sure we have the right settings enabled. Open up Exchange System Manager by clicking on Start > All Programs > Microsoft Exchange > System Manager. Expand the Global Settings container and select Properties for Message Delivery.

Click to the Intelligent Message Filtering tab and you'll see some new settings, for example, you can now reject messages that have a high SCL (SPAM Confidence Level). My settings are fairly conservative at 7 for the gateway and 6 for store junk configuration. I am also setting my gateway blocking action to archive the message so I never end up losing mail. You may want to set this to reject so that the sender of the message will be notified that you have not received the message. Your choice, mine is to archive.

Now on to enable the IMF on my SMTP server. Expand Servers > YOUR_SERVER > Protocols > SMTP and select the Properties for the Default SMTP Virtual Server.

On the General tab of the Default SMTP Virtual Server Properties click on Advanced, click on your SMTP server identity and click on Edit and check to Apply Intelligent Message Filter. OK, OK, Apply and you're set. You've got IMF.


Accessing Archived Messages

There is a great article on doing this by Mariėtte Knap and Marina Roos at SmallBizServer. Suffice to say, you first need to download the IMF Archive Manager and install it on your SBS/Exchange server. Then select Settings > Archive Folder and Settings > Pickup Folder and point them to the appropriate folders. Now you're done!

Note: By default Exchange 2003 SP2 and SBS CEICW use the following directories:
Archive Folder: C:\Program Files\Exchsrvr\Mailroot\vsi 1\UceArchive
Pickup Folder: C:\Program Files\Exchsrvr\Mailroot\vsi 1\Pickup


Read my other Exchange articles:

Publishing SenderID records for Exchange SP2 IMFv2
Enabling IMF 2 in Exchange 2003 SP2
Changing Exchange 2003 Store Database Limits
Exchange 2003 SP2 for SBS
Modifying the Outlook Web Access Login Page
Disabling NDR (non-delivery reports) on Exchange 2003
Setting up Exchange 2003 as an ATRN Client
Setting up Exchange 2003 as an ATRN Server


Additional Resources

Mariėtte Knap and Marina Roos's article on IMF
Exchange 2003 SP2 Webcasts
Top 10 Reasons to Install Exchange Server 2003 SP2
Exchange Server 2003 SP2 Release Notes
What Is New in Exchange Server 2003
Exchange Server 2003 Support for Mobile Device







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