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Protocol Sink Template

Exchange Server 2003

Protocol Sink Template

This content is no longer actively maintained. It is provided as is, for anyone who may still be using these technologies, with no warranties or claims of accuracy with regard to the most recent product version or service release.

The protocol sink template is a foundation on which you can build custom spam solutions and is written such that you can add your custom code directly into the template. The code within the template demonstrates the following:

  • How to evaluate whether a message's contents need to be filtered, based on one of the two new Extended Message Properties that are added to a message.
  • How to set the spam confidence level (SCL) on a message.
  • How to apply custom actions to messages based on the Block Threshold.
  • How to register a protocol event sink.

The protocol sink template supports three actions for messages assigned an SCL value higher than the Block Threshold:

  • No Action. The message is stamped with an appropriate SCL rating and allowed into the organization.
  • Reject. The message is not accepted and the connecting server is responsible for generating the non-delivery report (NDR).
  • Delete. The message is accepted and subsequently deleted. There is no notification sent to the sender or recipient that the message has been deleted.

The template binds to the END OF DATA event, which allows the filter to reject the message at the protocol level without accepting responsibility for the message. The benefit of this behavior is that the Microsoft® Exchange Server 2003 server is not responsible for delivering notifications (such as NDRs for messages targeted to non-existent users). However, there are no restrictions within the architecture that limit the sink to the END OF DATA event; thus, you can develop solutions that are instantiated after the END OF DATA event.

The following topics discuss how to use and customize the protocol sink template.

Template Code Files

Extending the Template

Building the Template