Configuring and Enabling Exchange Server Intelligent Message Filter


Topic Last Modified: 2007-01-22

After you install Microsoft® Exchange Server 2003 Service Pack 2, which includes the Exchange Server Intelligent Message Filter, you must configure the settings that you want to use in your organization. You also need to enable Intelligent Message Filter on each Simple Mail Transfer Protocol (SMTP) virtual server for which you want to filter unsolicited commercial e-mail (UCE).

Intelligent message filtering lets you block UCE on your gateway SMTP virtual servers. Gateway SMTP virtual servers are SMTP virtual servers that accept incoming Internet e-mail. Intelligent message filtering is defined globally, but enabled at the SMTP virtual server on a per-IP address basis.

This topic includes three key procedural topics, as follows, that help configure and enable Exchange Server Intelligent Message Filter.

Additionally, there are several topics there provide procedural information about Sender ID and connection filtering.

The Exchange Server 2003 Service Pack 2 Online Help, which is the main repository for much of the procedural information about Exchange Server 2003, contains other procedures that relate to configuration and enabling. Use the Search to find specific topics that you are interested in.

The online Help is downloadable at

Exchange 2003 supports connection filtering based on block lists. Connection filtering takes advantage of externally-based services that list known sources of unsolicited e-mail sources, dial-up user account lists, and servers open for relay based on IP addresses on block lists that they maintain. Connection filtering complements third-party content filter products. This feature lets you to check an incoming IP address against a provider's block list for the categories you want to filter. If a match is found on the provider's list, SMTP issues a "550 5.x.x" error in response to the RCPT TO: command.

You can also implement connection filtering without using a block list provider because you can create global accept and deny lists of SMTP addresses from which you want to globally accept or deny all e-mail messages.

Connection filtering is defined globally but enabled at the SMTP virtual server on a per-IP address basis. Different groups of users can log on with any number of IP address/TCP port combinations. You can decide which combinations, and therefore which users or groups, will have their messages filtered.

To configure connection filtering, you must first create and configure a connection filtering rule and then apply it at the SMTP virtual server level. The following topics explain how to perform each of these tasks: