For users where Outlook is in cache mode, they want to have their Outlook address book when they are offline. Outlook downloads the latest updates for their offline address book whenever they go online. Then they can use their updated address book when they are offline. In earlier Exchange versions Outlook connects to the Mailbox Server, but starting with Exchange 2010 Outlook connects only to the Client Access Server.

Offline address book generation server will be a mailbox server.

Where you can see below the generation server (If all roles are installed on the same box) the work flow remains the same

Offline Address book has Two Methods of Distribution.

For Outlook 2010, Outlook 2007, and Outlook 2003 SP2 clients it uses OAB version 4

1. Web-Based distribution

2. Public Folder distribution

In earlier versions like Outlook 2003, the offline address books are downloaded via Public Folders.

So if you don’t have Outlook 2003 in your environment , you can go ahead and disable Public Folder Distribution.

Beginning with Outlook 2007 , Outlook downloads the Offline Address book using the OAB url from the IIS Manager (Web-Based Distribution)

Offline address book updates itself depending on the update Schedule.

** This updates the items only on the Mailbox Server ** where users download the offline address book from the Client Access Server.

Now depending on the schedule the LZX files will get updated on the Mailbox Server.

**Offline Address book data are saved in the form of LZX files**

They are located by default at

C:\Program Files\Microsoft\Exchange Server\V14\ExchangeOAB

Every OAB will have their own GUID value.

Use PowerShell to find the GUID value of the default Offline Address Book.

You can customize the name of the OAB as per your requirement.

When you right click on the Offline Address book you can click on Update and the LZX files should get updated on Mailbox Server

** Date Modified Changes to Recent Date – LZX files are updating **

Now Outlook 2003 users should be able to download their Offline address books from Public Folders.

The Web-Based Distribution is much more efficient and must faster.

The files are copied to the Client Access Server where clients can download them.

For that reason this folder is shared where the Client Access Server can access it and copy it.

* Background Intelligent Transfer Service does this Job

The LZX files are copied to the Client Access server depending on the Polling Interval

You can find the settings for the Polling Interval as shown below -

By default the polling interval is 480 minutes.

You can find the OAB url , which is used for web based distribution on the URLs tab

By default internal URL doesn’t use HTTPS.

Microsoft Exchange File Distribution Services does this job on the Client Access Server

Now the same set of offline address book files are copied over to the Client Access Server

By default they are located at

C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\OAB

Because the offline address book is web based you can find the OAB Virtual Directory in IIS

It uses Windows authentication by Default.

To confirm that Outlook 2007 and Outlook 2010 clients are using Web Based Distribution,

hold your Ctrl key and right click on the Outlook icon, then click on Test Email AutoConfiguraion

Now using AutoDiscover , you can see the Offline Address Book URL as listed below with the correct Guid value

Client will Download their Own OAB depending upon their “Client Settings in Database Properties”

Or

If they have address book policies applied they would download their own OAB

Great !!

You learned how Offline Address Book works in Exchange 2010

It applies to Exchange 2010 RTM,SP1,Sp2

Regards

Satheshwaran Manoharan

Reference Link --
http://careexchange.in/?p=250