Are there published standards for who appears in the Outlook global address book in a hybrid Office 365/Exchange environment? Like disabled users, users with only a phone number, contacts in a non-synced OU, etc.
Note that we can manually change the settings in a mailbox to hide the user from address lists but a better solution would be to understand who appears and manage them holistically.
The built-in GAL that's automatically created by Exchange includes every mail-enabled object in the Active Directory forest. Includes all mail-enabled recipient objects in the organization (users, contacts, groups, dynamic distribution groups, and public folders.
In hybrid deployment, on-premise users will see all recipients in GAL, cloud users will see the synced recipients.
Yes, only key setting is “hide from address list”.