The Operations Manager Support Team Blog : Enabling Agent Proxy for a Class in System Center Operations Manager 2007

Agent Proxy needs to be enabled for several different management pack features to work properly.  Active Directory, Cluster and Exchange are few common management packs requiring Agent Proxy to be enabled, just to name a few.  Enabling the Agent Proxy security setting allows an agent to submit data on behalf of another source.  By default this setting is not enabled for any agents, so when we import a management pack that expects an agent to submit data not originating from that agent (i.e. other sources) we need to enable this security feature in order for some workflows to function.

The Operations Manager Support Team Blog : Enabling Agent Proxy for a Class in System Center Operations Manager 2007