Generating a new GAL and what to do with the OAB

[pazzoide76]

HI,
I have to recreate a New GAL because after a migration the Default Global Address List is without recepient filter and so I add a new mailbox the email address does not appear in the GAL and furthermore it is not updated (from the ecp it is in a non-updated state).
My environment consists of an Exchange 2016 cu23 with the latest security paths.
I was suggested to create a new GAL using these commands:

New-GlobalAddressList -name newGAL -Recipientfilter "((Alias -ne $null) -and (((ObjectClass -eq 'user') -or (ObjectClass -eq 'contact') -or (ObjectClass -eq 'msExchSystemMailbox') -or (ObjectClass -eq 'msExchDynamicDistributionList') -or (ObjectClass -eq 'group') -or (ObjectClass -eq 'publicFolder'))))"

Update-GlobalAddressList newGAL

Once I create the newGAL does it become the deafult GAL for all users?
Do I have to do something with the OAB? Or does the OAB point directly to the newGAL?

Thank you

[#2 · Accepted solution]

When you create a new Global Address List (GAL) using the commands you provided, it doesn't automatically become the default GAL for all users. The default GAL is determined by the Default Global Address List setting in Exchange. To set the newGAL as the default GAL, you need to modify the Default Global Address List setting.

To set the newGAL as the default GAL for all users, you can use the following command:

Set-GlobalAddressList -Identity "newGAL" -IsDefault $true

This command sets the IsDefault parameter to $true, indicating that the newGAL should be the default GAL.

Regarding the Offline Address Book (OAB), the OAB is a separate component in Exchange that contains a copy of address list information that's used by Outlook clients in cached mode. The OAB is generated based on the GAL and is updated periodically. When you create a new GAL, you need to make sure that the OAB is associated with the newGAL.

To associate the OAB with the newGAL, you can use the following command:

Get-OfflineAddressBook | Set-OfflineAddressBook -GlobalAddressList "newGAL"

This command retrieves all the OABs in your environment and sets the GlobalAddressList parameter to "newGAL" for each OAB, effectively associating them with the new GAL.

After setting the newGAL as the default GAL and associating the OAB with it, you can initiate a manual update of the OAB to ensure that it reflects the changes made. You can do this using the following command:

Update-OfflineAddressBook -Identity "Default Offline Address Book"

Replace "Default Offline Address Book" with the actual name of your OAB if it differs.

By following these steps, the newGAL should become the default GAL for all users, and the OAB will be updated accordingly.

[#3]

@Max_Kaiser 

Thank you