The backboning process must handle several types of message recipients. These recipient addresses may need to be translated to the foreign system format before they are encapsulated.
Only Responsibility-TRUE recipients appear in the message transfer envelope (MTE) recipient table. These are recipients to whom the gateway must deliver the message. These addresses can be either native Microsoft Exchange Server addresses or one-off addresses. If they are native addresses, the gateway must resolve them to proxy addresses for the foreign system. If they are one-off addresses, they must be of the type that the gateway requires.
The message originator address appears both on the MTE and on the message content. The gateway should insert the originator’s proxy address into both the MTE and the message content so that replies can be delivered to the originator.
If the message is addressed to a distribution list (DL), the message’s recipient table contains the distinguished name (DN) of the DL. When Microsoft Exchange Server wraps the message in an MTE to send to the gateway, it breaks down the DL and places a Responsibility-TRUE recipient in the MTE’s recipient table for each DL member. The DL itself remains as a single entry in the recipient table.
When the DL members are listed as individual recipients in the MTE recipient table, each one has a PR_RECIPIENT_NUMBER property. This property is the number of the DL entry that contains the recipient in the message content recipient table.
Each individual Responsibility-TRUE recipient must be resolved to its proxy address representation. The DL in the message content recipient table must be resolved to its proxy representation before the message content is encapsulated in TNEF.