How to create a new public folder tree and store in Exchange 2000 Server and in Exchange Server 2003

This article describes how to create and implement multiple public folder trees. Both Microsoft Exchange 2000 Server and Microsoft Exchange Server 2003 gives administrators the flexibility to create multiple public folder trees. These public folder trees are also named "top-level hierarchies."

In Microsoft Exchange Server version 5.5, the system is constrained to a single public folder tree that is named Public Folders. In Exchange 2000 Server and in Exchange Server 2003, there can be multiple public folder trees.

With multiple public folder trees, administrators can separate internal public folder hierarchies from hierarchies that have external users accessing them. This behavior keeps external users from physically accessing internal public folders. Additionally, administrators can separate groups or departments in an organization.

When Exchange 2000 Server or Exchange Server 2003 is installed, a default public folder tree is created. This public folder tree can be accessed from all MAPI and Internet clients, such as HTTP, Internet Message Access Protocol (IMAP), and Network News Transfer Protocol (NNTP). Subsequent public folder trees are only available from HTTP and NNTP clients.

Create a new public folder tree

1. Start Exchange System Manager.
2. Locate the Folders container.
3. Right-click the Folders container, click New, and then click Public Folder Tree.
4. Choose a name for the public folder tree and type it in the Name field; it is the only required field. The Details tab displays the creation and the modification dates. Additionally, the Details tab lets you enter administrative notes.

Create a new public folder store

1. Start Exchange System Manager.
2. Click the Storage Group where the folder store will be stored.
3. Right-click the storage group to which you want to create the new public store, click New, and then click Public Store. The Properties page for the new store appears.
4. Choose a name for the public store, and type it in the Name field.
5. To choose the Associated public folder tree, click Browse, and then select the public folder tree to which you want to apply this public store. Click OK.
6. Configure the remaining parameters for your new store, and then click OK to save the properties.

After you click OK to save the properties, you receive a dialog box that prompts you whether you want to mount the new store or not. If you click Yes, the store tries to mount. You will be notified if it was successful.

To verify what Public Store is associated with a public folder tree, under the Folders container, right-click the Public Folder Tree , and then click Properties . On the General tab, you see which public stores are associated with this public folder tree.

Create an additional Folders container

A Folders container in an administrative group is required before you can create a new public folders tree within that administrative group. However, with multiple administrative groups in an Exchange 2000 Server and in an Exchange Server 2003 organization, only the First Administrative Group contains a Folders container by default.

To create a Folders container in another administrative group:

1. Right-click the administrative group that you want to create a Folders container in.
2. Click New, and then click Public Folders Container.
3. The Folders container now appears.

NOTE: In Exchange 2000 Server and in Exchange Server 2003, only one Folders container is permitted for each administrative group. After you create a Folders container in an administrative group, if you right-click the administrative group, and then click New, you no longer see the option to create a new public folders container.

Troubleshooting

If no unassociated public folder tree exists, you receive the following error message when you try to create a new public folder store:

For more information about public folder stores, click the following article number to view the article in the Microsoft Knowledge Base: For more information about permission assignment for non-MAPI public folder tree, click the following article number to view the article in the Microsoft Knowledge Base:

Rules on using multiple public folder

The following section describes the rules that you must follow when you create multiple public folder stores and multiple public folder hierarchies. Additionally, this section describes the relationship of public folder hierarchies to public folder stores in Exchange 2000 Server and in Exchange Server 2003.

Terminology

A public folder hierarchy is also known as a public folder tree and as a TLH. The MAPI public folder tree is also known as the MAPI TLH. A non-MAPI TLH is also known as an application TLH or a general purpose TLH.

Rules for creating public stores and hierarchies

This section lists the rules that you must follow to create multiple public stores and multiple public hierarchies in Exchange 2000 Server or Exchange Server 2003:

1. You can only have one public folder hierarchy per public store.
2. An server that is running Exchange 2000 Server Standard or a server that is running Exchange Server 2003 Standard can only have one public folder store.
3. An Exchange 2000 Server Enterprise server can have up to 19 stores. This includes up to four mailbox stores and 1 public folder store for the first storage group and up to five mailbox stores for the remaining three storage groups. An Exchange Server 2003 server can have up to four storage groups. Each storage group has up to five databases. These five databases contain either mailbox stores or public folder stores.
4. A server cannot have multiple public folder stores that contain the same public folder hierarchy.
5. You can only create a new public folder store if a public folder hierarchy exists that is not currently assigned to a public folder store on the server.
6. If no public folder hierarchy exists that is not currently assigned to a public folder store on the server:
   1. Right-click the Folders container to create a new public folder tree.
   2. Create a new public folder store on the server and assign the new public folder tree to the new public folder store.
7. There can only be one MAPI public folder hierarchy in the Exchange 2000 or Exchange 2003 organization.

Public folder hierarchy types

In Exchange 2000 Server and in Exchange Server 2003, there are two types of public folder hierarchies. One is the MAPI public folder hierarchy. This public folder hierarchy is the only MAPI public folder hierarchy in Exchange Server 4.0 - 5.5 which also exists in Exchange 2000 Server or Exchange Server 2003. The other type of public folder hierarchy is the application public folder hierarchy. This hierarchy exists only in Exchange 2000 Server and in Exchange Server 2003, This heirarchy does not exist in earlier versions of Exchange Server.

A TLH is the root of a public folder tree. In Exchange Server there was only one TLH This TLH was named "Public Folders." In Exchange 2000 Server and in Exchange Server 2003, there can be several TLHs. The "Public Folder" TLH is one of many public folder trees. The "Public Folder" TLH is typically known as the MAPI TLH.

The MAPI TLH performs the same tasks in Exchange 2000 that it performs in Microsoft Exchange Server. The MAPI TLH will replicate with the Exchange Server public folder tree. However, in Exchange 2000 Server and in Exchange Server 2003, there can also be multiple additional trees. These multiple additional trees are typically known as Application TLHs (App TLH).

When you install Exchange 2000 Server or Exchange Server 2003, a default public folder tree is created. This public folder tree can be accessed from all MAPI (Microsoft Outlook) clients and Internet protocol clients, such as HTTP, Internet Message Access Protocol, Version 4rev1 (IMAP4), and Network News Transfer Protocol (NNTP). Later (non-MAPI) public folder trees are only available from HTTP and NNTP clients. Post Office Protocol version 3 (POP3) clients cannot access either MAPI public folder trees or non-MAPI public folder trees.

Additional information

For more information about the MAPI public folder tree, click the following article number to view the article in the Microsoft Knowledge Base: For more information about non-MAPI public folder trees, click the following article number to view the article in the Microsoft Knowledge Base: For more information about public folder hierarchies in Exchange 2000, click the following article number to view the article in the Microsoft Knowledge Base:

Unable to assign multiple public folders to a single public folder tree

You can programmatically create a second public folder store through Collaboration Data Objects for System Management . Additionally, you can configure the folder tree item as a tree that is already being used by another public folder store on the server.

This scenario is unexpected. You cannot create a second public folder store on the same server that is associated with the same public folder tree when you use Exchange System Manager. This is not a supported configuration.

Status

Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server and Microsoft Exchange Server 2003.
Note Collaboration Data Objects for System Management is an API that enables administrators to access management information about an Exchange 2000 or an Exchange Server 2003 programmatically. This management information includes databases and mailboxes. The Emo.dll file provides these services.

Typically, a public folder tree on an Exchange 2000 or Exchange Server 2003 can be associated with only one Exchange 2000 or Exchange 2003 public folder store on a particular server. If an unassociated public folder tree does not exist, you receive the following error message when you try to create a new public folder store by using Exchange System Manager:
After you use Exchange System Manager to create a new public folder tree on the server, the only available public folder tree that the Exchange System Manager displays for that server that is available to select is the new, unassociated public folder tree when you try to create a new public folder store.

Additionally, on an Exchange 2000 or Exchange 2003 cluster server, you must make sure that a public folder tree is unique to all virtual computers of the cluster so that public folder stores on the server are not associated with the same public folder tree. Otherwise, in a failover scenario, you may have multiple public folder stores that try to run on the same node that are associated with the same public folder tree.

Typically, you cannot assign the same public folder tree to two public folder stores on the same server. You can only create two public folder stores on the same server associated with the same public folder tree programmatically, as described in this article. However, do not perform this procedure programmatically, as Microsoft does not support this configuration.