The MAPI specification defines the following two kinds of properties:
- Standard MAPI properties
- Named properties (also known as named props)
A named property is a custom property that is known by the property's name instead of by a coded ID. The MAPI specification defines many property tags. However, the MAPI specification also lets vendors extend the defined MAPI property set by creating their own properties or by publishing the property type together with a string value or with a numeric value.
To perform a Get operation or a Set operation on a named property, a client or a service provider must ask the object on which the Get or Set properties call is made to create an ID that corresponds to the published property name. In this situation, only the property name is fixed. The ID is dynamically created. The ID for the named property must be produced by the service provider. The service provider must maintain an internal map of property names to property IDs. The range for named properties is 0x8000 to 0xFFFF. This range gives a service provider an effective range of 32,766 possible entries from which to allocate IDs and from which to return those IDs to the requesting client.
The Exchange information store uses named properties and property IDs for tasks such as processing SMTP X-headers and DAV properties that are not well known.
Note SMTP-X headers are custom headers that programs and companies use. For example, if you send a message to a public folder, and that message has an
X-spam-confidence level SMTP-X header that your company uses, a named property is created. SMTP-X headers differ from standard SMTP headers such as
To,
From,
Date, and so on.
Exchange 2000 Server has a limit of 32,766 property IDs for each messaging database. If you use many named properties, this limit may be reached over time. After the limit of 32,766 property IDs is reached, Exchange 2000 Server cannot assign any more property IDs. Therefore, you must save the public folder content from the affected server, and then remove and re-create the public folder store.
Microsoft Exchange Server 2003 lets you set lower quota limits for property IDs. This functionality gives you more flexibility in case you experience this issue. By setting the property ID values to a lower limit, you can receive earlier notification about the depletion of property IDs. Therefore, you can take action before the range of property IDs is exhausted.
For more information about how to troubleshoot public folder replication issues, click the following article number to view the article in the Microsoft Knowledge Base:
842273�
How to troubleshoot public folder replication problems in Exchange 2000 Server and in Exchange Server 2003
For more support information for Exchange 2000 Server, visit the following Microsoft Web site: