Updating the Global Address List and Offline Address Book in Exchange 2010 and 2013

We will firstly update the GAC (Global Address List) - this is what clients will query when an active connection is established with Exchange:

Get-GlobalAddressList | Update-GlobalAddressList

We also need to take into account clients using the Offline Address Book (this is used when clients are offline and are using Cached mode:

Get-OfflineAddressBook | Update-OfflineAddressBook

And finally (if you are using Exchange 2010) after updating the GAC and OAB (which reside on the mailbox server) we need to instruct the File Distribution Service on the Client Access Server to re-poll the OAB and GAC:

Get-ClientAccessServer | Update-FileDistributionService

Although if you are using Exchange 2013 the File Distribution Service has been scrapped. The OAB is now stored in an Organizational Mailbox oposed to: %ExchangeInstallPath%\ClientAccess\OAB\

The OAB is now accessed over HTTP/S via an OAB URL that is provided as part of the autodiscover process.

The following describes the process of the OAB being requested by an end user:

- Performs initial authentication for end user (Basic, NTLM etc.)
- Queries AD to find the nearest Organizational Inbox for the user.
- Queries AD again to identify the mailbox database assosiated with the identified Organizational Inbox
- Queries Active Manager to identify which mailbox server is holding the active copy of the identified mailbox database.
- The CAS proxies the client request to the mailbox server - hence allowing the transmission of the OAB.