Hello.  I have two Exchange 2013 CU5 Standard servers in a DAG.  Both servers have both the CAS and Mailboxes roles installed.   The servers are running Server 2012 Standard.  Our clients use Outlook 2010 in online mode.  In Outlook, I can click on Address Book, on the Menu Bar to bring up the Global Address List.  By right clicking on the "Global Address List - user@domainname" item, I can select properties.  When I do, I see the following.

Microsoft Exchange Address Book Provider

The current server is:

<AlphanumericIdentifier@domain.com>

The identifier is not the GUID of either one of my Exchange servers, nor is it  the GUID of a domain controller.  How do I resolve that Identifier to a meaningful name, such as the name of a global catalog server?

I was able to determine that the identifier is not the GUID of the user's Exchange mailbox.  Rather it is a different attribute, the ExchangeGUID, of the mailbox.

• Marked as answer by vltdiv 13 hours 51 minutes ago