XCON: Cannot Configure MTA to Provide Adequate Message Control

ID: Q186714

The information in this article applies to:

Microsoft Exchange Server, version 5.5

SUMMARY

Microsoft Exchange Server does not support the following features:

You cannot configure the message transfer agent (MTA) so that all messages with a given importance level time out after a certain period of time.

You cannot configure a given connection so that messages sent through the connection are stored in the outbound message queue until a certain number of messages have been stored in the queue, or until the entire queue has reached a certain size.

You cannot configure a given connection so that certain types of messages cannot be sent through the connection. For example, system messages, non-system messages, or messages sent with urgent, normal, or low importance.

MORE INFORMATION

Microsoft recognizes the need for the features described above. We have modified the Exchange Server 5.5 MTA so that the following features are supported.

NOTE: The override changes mentioned in this article affect the Site and X.400 Connectors using the MTA as their transport.

Priority Time-Outs

After you obtain this feature, you can configure the MTA so that all messages with a given importance level time out after a certain period of time. When you obtain the feature, three new registry values are created under the following key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeMTA \Parameters

The following registry values are created:

Value Name: Message timeout (urgent)
Data Type: REG_DWORD
Description: Messages with high importance should time out after the specified number of minutes.

Value Name: Message timeout (normal)
Data Type: REG_DWORD
Description: Messages with normal importance should time out after the specified number of minutes.

Value Name: Message timeout (non-urgent)
Data Type: REG_DWORD
Description: Messages with low importance should time out after the specified number of minutes.

If one of the above values is set to 0 (zero), messages with the associated importance level are never sent. In addition, note that these values do not apply to system messages.

Threshold Limits

After you obtain this feature, you can configure a connection so that messages sent through the connection are stored in the outbound message queue until a certain number of messages have been stored in the queue, or until the entire queue has reached a certain size. You can also specify that messages with high importance should be sent immediately, even if the queue's threshold has not been reached. When you obtain the feature, three new registry values are created under the following key

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeMTA \Parameters\connection

where connection is the associated connection.

Value Name: Content Length Threshold
Data Type: REG_DWORD
Description: Messages are stored in the outbound message queue until the total size of all the messages reaches the specified number of kilobytes (KB).

Value Name: Queue Length Threshold
Data Type: REG_DWORD
Description: Messages are stored in the outbound message queue until the specified number of messages is stored in the queue.

Value Name: Urgent Overrides Thresholds
Data Type: REG_DWORD
Description: If this value is set to 1, messages with high importance are sent immediately, even if the above thresholds have not been reached. If this value is set to 0, messages with high importance are not sent until the threshold is reached.

If the Content Length Threshold or Queue Length Threshold registry value is set to 0 (zero), the value is ignored. If both registry values are set to a value other than 0, messages are stored in the queue until either of the specified thresholds is reached.

Message Type and Priority Restrictions

This feature enables you to specify which messages can use a particular connector based on message type or priority. For each connector you can prohibit system, non-system, urgent (high importance), normal, or non-urgent (low importance) messages. You can also specify that urgent messages override the schedule for a connector and are sent immediately; other messages remain in the queue until the next scheduled time.

The per-connector message limits are set on each connector object by editing the raw properties of the connector. The limits are set using the Heuristics attribute. The value of the Heuristics attribute is the decimal integer sum of the following values for each limit you want to set:

Attribute: Disallow system
Description: If this value is set to 4096, system messages cannot be sent through the connection.

Attribute: Disallow non-system
Description: If this value is set to 8192, non-system messages cannot be sent through the connection.

Attribute: Disallow Urgent
Description: If this value is set to 16384, messages with high importance cannot be sent through the connection.

Attribute: Disallow Normal
Description: If this value is set to 32768, messages with normal importance cannot be sent through the connection.

Attribute: Disallow Low
Description: If this value is set to 65536, messages with low importance cannot be sent through the connection.

Attribute: Urgent ignore schedule
Description: If this value is set to 131072, messages with high priority are sent immediately, even if the connection's schedule indicates that the message should not be sent immediately.

To set these per-connector limits:

WARNING: Using the raw mode of the Exchange Server Administrator program (admin /r) incorrectly can cause serious problems that may require you to reinstall Microsoft Windows NT Server and/or Microsoft Exchange Server. Microsoft cannot guarantee that problems resulting from the incorrect use of raw mode can be solved. Use raw mode at your own risk.

Start the Microsoft Exchange Server Administrator program in raw mode by typing the following at a command prompt:

c:\exchsrvr\bin\admin /r

In the appropriate site Connections container, click the connector object.

On the File menu, click Raw Properties.

In the List attributes of type box, click All.

In the Objects attributes list, click Heuristics.

In the Edit value list, type the value (or sum of the values, if you wish to implement more than one type of restriction) for the limits you want to set, and then click Set.

These features are included in the latest Microsoft Exchange Server version 5.5 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words: connector heuristic admin administrator program raw mode

Keywords : XCON exc55
Version : winnt:5.5
Platform : winnt
Issue type : kbhowto