This article was previously published under Q253828
One of the main tasks of the Recipient Update Service is to populate the showInAddressBook attribute for objects in Active Directory. Each mail-enabled object has this attribute, including users, contacts, groups, public-folders and any other object in Active Directory that supports showInAddressBook attribute and has a mailNickname attribute.
Every time that a user, a group, or any object is added or modified in Active Directory, the Recipient Update Service picks up that object, determines which of the available address lists it belongs to, and adds that address list to the showInAddressBook attribute of the object.
One exception for this is if the mailbox is hidden. In that case, the msExchHideFromAddressLists attribute is set to TRUE, so the Recipient Update Service will not stamp any address lists, and will remove any that are already present on the attribute.
The showInAddressBook attribute has two purposes. The first is to let people see the entry listed in the address list by means of Messaging Application Programming Interface (MAPI) client, such as Microsoft Outlook. The second purpose is to allow users to "resolve a name" on a MAPI client.
By default, there are several address lists configured in Microsoft Exchange 2000 Server and Exchange Server 2003. The most important is the default global address list (known as the global address list in Exchange Server 5.5). Exchange 2000 and Exchange 2003 allow you to have several global address lists, and several other address lists with a much richer definition than earlier versions of Exchange Server. For example, you can create an address list called "Top Executives" that searches for entries that have "VP," "President," "CEO," or "Director" in the title.
By default, Exchange 2000 and Exchange 2003 provide the following address lists, plus the default global address list:
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How Exchange Uses the ShowInAddressBook Attribute to Resolve Names
To set up Microsoft Outlook to access an Exchange mailbox, you must create a profile for that mailbox. When you configure the Microsoft Exchange Server service in the profile, one of the steps is to enter your Exchange server name, and your mailbox alias.
When you click the Check Name button, Outlook attempts to resolve the alias to a mailbox on the Exchange server. Outlook uses MAPI to contact the Exchange server that you specify and queries to see if there is an entry that matches the alias that you entered. The server then searches for any mail-enabled objects that belong to at least one address list and that also match the alias. After the name has been resolved, the client is ready to log on.
If a user does not have any address lists in the showInAddressBook attribute, it does not belong to any address list. Therefore, that user will not be able to resolve their alias to a mailbox.
This behavior occurs if the mailbox is hidden, which causes the msExchHideFromAddressLists attribute to be set to TRUE. In this case, you cannot resolve the name, and therefore, cannot create a profile in Outlook. To be able to access this mailbox, you need to unhide this object, create the profile, and then hide it again.