Offline Address Book - Birds eye-view

What is an Offline Address Book?

An offline address book is a container that stores a collection of offline address lists. Administrators configure available offline address books, and Outlook users can choose which offline address lists they want to download.

What is an Offline address list?   

An offline address list is a set of address lists in files that are created and stored on an offline address list server. Users who work offline can connect to an Exchange Server computer and download offline address lists to obtain information about other users in the organization. When you create an offline address book, the specified address lists are converted to a separate set of files and stored in a public folder. When users download the offline address book, this data file is used as the source of information. Outlook 2003 uses offline address book to provide offline access to directory information from global address list (GAL) and from other address lists.

• Exchange generates new offline address book files & places them in a special public folder, known as a system folder, for Outlook to download.
• Offline address book files are compressed before they are added to offline address book system folders so that the download to Outlook is minimal.
• Outlook is scheduled to check periodically for new offline address book files in these system folders, and download the required files.
• Offline address books typically contain at least one address list that represents the global address list (GAL).
• Users who are working offline can use this global address list with Messaging Application Programming Interface (MAPI) e-mail clients.

How it's getting created?

• Several Exchange Server components work with Active Directory to generate and maintain offline address books.
• After an offline address book has been created
• either automatically by Exchange Setup
• or manually by an administrator using Exchange System Manager
• Exchange Server and Active Directory work together to maintain the offline address book, keeping it synchronized with changes that may be made in the directory.

Where it will be displayed?

• System folders can be displayed in Exchange System Manager, enabling an administrator to view the files that make up the offline address book

What will be the size of Offline address book? 

• Offline address book sizes can vary from a few megabytes to a few hundred megabytes. (It depends on various factors)

Note: Address book size refers to the size of the compressed offline address book files on the Exchange Server, and not the uncompressed, expanded file size for the offline address book files on the Outlook client.