IMF: Gateway thresholds per server

So far we've known that Exchange Server 2003's content filter - the Intelligent Message Filter (IMF), uses Gateway and Store thresholds and (Gateway) action that are configured once in Global Settings | Message Delivery | properties | Intelligent Message Filtering. These global settings apply to all SMTP Virtual Servers on all Exchange Servers in the Org that have IMF enabled.


Figure 1: Configuring Intelligent Message Filter's Gateway and Store thresholds for the entire Organization

Evan Dodds reveals the ability to configure per-server Gateway threshold and action for IMF in "Configure IMF gateway settings per server".

To enable the per-server Gateway thresholds, two registry values need to be created as follows:
Registry Key: HKLM\Software\Microsoft\Exchange\ContentFilter



Value: GatewayThreshold
Value type: REG_DWORD
Value data: 0-9

Value: GatewayAction
Value type: REG_DWORD
Value Data:
0x0 = No Action
0x1 = Delete
0x2 = Reject
0x5 = Archive

The above method allows you to control the Gateway threshold and action per server. You cannot control the Store threshold per server.

So the answer is, yes, it's possible using this undocumented registry hack, and Evan also suggests when one may need to use it.