In most organizations, the Default Global Address List, or GAL, more than fits their needs. However, some organizations like to create custom GAL’s. This could be either for the use of address list segregation with a hosted solution, or the Default GAL lists service accounts that the users shouldn’t see. Creating a custom GAL is easy, especially in Exchange 2007.
However, an issue may arise when after you have created this custom GAL, regarding users in cached mode in Outlook. When a user is in cached mode, their GAL is actually the Offline Address Book. By default, the Default Offline Address Book includes the Default GAL as its source. So this custom GAL you just created isn’t seen by the users in cached mode.
The trick to this, is to create a new Offline Address Book, and add the new GAL to it. For this, you will need to use powershell. So lets say you have a custom GAL called “Test GAL” in Exchange 2007. You can check what GAL’s you have by running the Get-GlobalAddressList command:
We are going to create a new Offline Address Book, with the “Test GAL” as the included GAL to generate the OAB from. Also, don’t forget, a specific Mailbox server has to be responsible for generating the OAB, so we are going to use server Test-EX07B. The command will be as follows:
New-OfflineAddressList –Name “Test OAB” –AddressLists “Test GAL” –Server Test-EX07B
So you have your new “Test OAB”. Just a heads up, while in the Exchange Management Console, you’ll be able to edit any item of the new OAB, except the address list. This means you can change the name, and set the delivery mechanism for public folder distribution or web services distribution, but you can only add address lists through the shell:
Now all thats left to do is add the “Test OAB” as the default Offline Address Book for the database’s in your organization. You can either right click on each database in your organization, select the Client Settings tab and change to the “Test OAB”:
Or, if you want to do it en masse for every database in your organization, you would run the following command from the shell:
Get-MailboxDatabase | Set-MailboxDatabase –OfflineAddressBook “Test OAB”