The CAS servers poll for changes every 8 hoursĪs mentioned before, this is only for Exchange 2010, Exchange 2013 avoids this step through the use of proxying The OAB generation server creates the new OAB once per day at 5am This can occur even though no errors are present within the OAB rebuild process. may not be available even though such changes have been made in Active Directory. Because of this, a new user may not be visible in the address book, or changes to a user’s name, address, etc. The OAB is rebuilt and downloaded on a default schedule as shown below. When Outlook users are running in cached mode, they rely on the Offline Address Book (OAB) to provide them with access to one or more addresses (that are always available when they are connected directly to Exchange) Some examples of these attributes includes: You can see the list of attributes that will be put into the GAL using Get-OfflineAddressBook 'Default Offline Address Book' | select -expandproperty configuredattributes If these attributes are present, then the AD Objects that are Mail-Enabled or Mailbox-Enabled will appear in the GAL – and ultimately the Offline Address Book. The GAL will only present objects that have AD Attributes beginning with msEXCH* (and some others) populated that it uses to filter on. GAL Objects are directly viewable in the Exchange Management Console/Shell and OWA and Microsoft Outlook BUT ONLY IN ONLINE MODE – not cached mode. The GAL contains information for all email enabled users, Distribution Groups, and Shared Mailboxes and Exchange Resource Mailboxes. *** NOTE: The GAL is essentially a real-time / online representation of AD Objects that are Mail Enabled for Microsoft Exchange *** This situation however is extremely rare since the default maintenance time on Exchange is at 5:00 AM and updates and downloads are usually performed during working hours.
This means that in the worst possible scenario, an update to the Address Book won’t become available to the user until about 48 hours after the change.