High Quality Content by WIKIPEDIA articles! The Global Address List (GAL) also known as Microsoft Exchange Global Address Book is a directory service within the Microsoft Exchange email system. The GAL contains information for all email users, distribution groups, and Exchange resources. Digital IDs certificates generated by Microsoft Exchange Server Advanced Security IIS or by Microsoft Exchange Key Management Server (KMS) are automatically published in the Global Address Book. Users of Microsoft Outlook can publish to GAL their externally generated PKI certificates that are used for secure e-mail.