How offline Address books works in Exchange 2013

What is a Offline Address book ?

For Users where Outlook is in Cache mode, They got to have their Outlook Address book Updated ,when they can access the latest Address book while they go offline.
If Outlook is left running constantly in Cached Exchange Mode, it updates the Offline Address Book automatically about once a day, depending on Address Book updates on the server running Exchange. To initiate these updates manually, do the following:

1. On the Tools menu, point to Send/Receive, and then click Download Address Book.
2. Under Information to download, click Full Details or No Details.

So that they can use their updated address book when they are offline.
Earlier Exchange 2010 Version. Outlook Connects to the Client Access Server for MAPI Connectivity.
But From Exchange 2013 Outlook Connects to the Client Access Server
And the requests are proxied to the Mailbox Server
Lets See what is happening in the Background
In my Case all Roles are installed on the Same Server
Offline Address book Generation Server will be a Mailbox Server.
You can find a OAB Virtual Directory in IIS – in the Client Access Server
The Request to the Client Access (OAB Virtual Directory) Proxies the request to the “Exchange Back End” (OAB Virtual Directory) which is a Mailbox Server Containing OAB Files where client downloads the OAB Files


Offline Address Book Storage Location
Offline Address book Stores its files to a “System Mailbox” Which is called as “Organizational Mailbox” Where if the database fails the Organization Mailbox can failover using Database availability Group.
where the request from the Client doesn’t fail . It looks the database which owns the Organization Mailbox and OAB files are copied over to the Disk in the appropriate Mailbox Server and it has been to the Client.
Where OAB is no more a single point failure in Exchange 2013
To See which Organizational Mailbox is storing OAB files –

Get-Mailbox –Arbitration | where-Object {$_.PersistedCapabilities –Like "*OabGen*"} | FL Name,Persisted*

You can see – “OrganizationCapabilityOABGen”

Then Its Copied over to the disk in the Form of LZX files
Default Location: (Differs if you install Exchange on a Different Drive)
C:\Program Files\Microsoft\Exchange Server\v15\ClientAccess\OAB

They will be copied to the disk in the Form of LZX files

How to find the Offline Address book url , which is used for OAB Downloads
From Outlook 2007 ,Outlook 2010 and So on , Outlook Downloads Offline Address book using the OAB Url Web-Based (IIS)

Get-OabVirtualDirectory | FL Name,*Url*

You got to Specify the External Url if you are going to use Outlook Anywhere
using Set-OabVirtualDirectory Cmdlet

To Find which OAB a User Downloads
Go to a Client Machine
Hold your Ctrl Key and Right Click on the Outlook icon – Click on Test Email AutoConfiguraion

Now Using AutoDiscover , You can see the Offline Address book URL as listed below with the Correct Guid Value

To Find the GUID Value of the Offline address book

Get-OfflineAddressbook | FT Name,Guid

Client will Download their Own OAB depends upon their “Client Settings in Database Properties”
If its not specified – By Default they will download the “Default Offline address book”

Or
If they have address book policies applied They would Download their own OAB respective to the Policy

Get-Mailbox "Mailbox Name" | FL Name,AddressBook*

How Often Offline Address book Updates itself
** This Updates the Items only on the Mailbox Server – Stores in the “Organization Mailbox” as explained earlier

Get-Offlineaddressbook | FL Name,Schedule

Now Depends on the Update Time “Organization Mailbox” will get updated on the Mailbox Server.
**Offline Address book data are saved first only on the Organization Mailbox**  Then Once its got Updated it Serves the latest data to the Clients
How to Force update the Offline Address book

Get-OfflineAddressbook "Default Offline Address book" | Update-OfflineAddressBook

To Verify
**Property Last Touched Time Gets updated**

Get-OfflineAddressbook | FT Name,LastTouch*

or
You can Restart
Microsoft Exchange Mailbox Assistant Service
As that’s the service does all the job in the background

Restart-Service MsExchangeMailboxAssist*

Additional Info –
Type of Distribution used in Exchange 2013
Exchange 2013 Uses only One Type of Distribution –Web-Based Distribution
1 .Web-Based distribution

2. Public Folder distribution (Removed in Exchange 2013)
Earlier
Earlier Version Like Outlook 2003, Offline address book are Downloaded via Public Folders,
Offline Address Book Version In Exchange 2013
For Outlook 2010, Outlook 2007 clients it uses OAB version 4

Get-OfflineAddressbook

Great !!
You Learnt How Offline Address book works in Exchange 2013