Working with Inbound Messages of Custom Address Types

A logical thing to do here would be trying the same trick we did for EDK messages: changing RCPT TO property and just dropping files into the gateway's In folder. I am speaking about the gateway specially configured to handle custom address types here.

This works if you properly install an Addr-Type object for your address type. This will not work if you just reconfigure your gateway. The Addr-Type object associates your address type with a proxy generation DLL that generates custom e-mail addresses for each Exchange server recipient. Attempting to use the gateway without properly installed Addr-Type object will fail on incoming messages. For example, if you just change RCPT TO property and drop the file into gateway's In folder it will not be delivered. You will get a non-delivery report back into gateway's Out folder saying that "The recipient was detected looping within the message transfer service". Further sections in this chapter explain how you can reuse proxy generation sample code provided with EDK with your address type.

Customizing sample gateways obviously is not the best way of gateway development. But this approach is working and in fact gives you great power. Messages as they appear in folders do not have any MAPI properties. They are files pre formatted for easy SMTP exchange with a foreign system. You can also send attachments. Sample gateway specifically configured allows you to avoid MAPI development! You can use this as a starting point and work in co-operation with sample gateway. For example, you could implement a Windows NT service, which operates with files in gateway's In and Out folders. It would get an outgoing message from its Out folder and transmit it to the foreign system. It would put messages coming from the foreign system into its In folder. Perhaps this would be just enough for many situations! Very little development is needed for that. In fact, familiarity with MAPI or Exchange environment is not needed at all!