| Platform SDK: Exchange Server |
The PR_EMS_AB_MDB_UNREAD_LIMIT property contains the maximum number of unread messages allowed in a gateway mailbox.
| Header file: | EMSABTAG.H |
| Applies to: | Mail-Gateway objects (directory objects). These objects appear to MAPI as messaging_user objects, which are accessible through the MAPI IMailUser interface. |
| Identifier: | 0x80d3 |
| Property type: | PT_LONG |
| Access: | Read/write |
When the number of unread messages in a gateway's mailbox folders (such as MTS-IN and MTS-OUT) reaches the limit set by the PR_EMS_AB_MDB_UNREAD_LIMIT property, the information store stops the transfer of messages from the MTA to the gateway for the length of time specified by the PR_EMS_AB_MDB_BACKOFF_INTERVAL property.
The PR_EMS_AB_MDB_UNREAD_LIMIT, PR_EMS_AB_MDB_BACKOFF_INTERVAL, and PR_EMS_AB_MDB_MSG_TIME_OUT_PERIOD properties are related as follows:
If a gateway service is turned off, messages can continue to be delivered to the gateway's MTS-OUT folder until the number of unread messages reaches PR_EMS_AB_MDB_UNREAD_LIMIT. When this limit is reached, delivery to the gateway stops and additional messages back up in MTA delivery queues.
Unread messages in MTS-OUT are removed and nondelivery reports are generated after PR_EMS_AB_MDB_MSG_TIME_OUT_PERIOD minutes. Within PR_EMS_AB_MDB_BACKOFF_INTERVAL minutes, messages can once again be transferred from the MTA to the gateway's MTS-OUT folder.
PR_EMS_AB_MDB_BACKOFF_INTERVAL, PR_EMS_AB_MDB_MSG_TIME_OUT_PERIOD