|Configuring Active Directory Authentication / About Active Directory Authentication|
For faster authentication, you can use a global catalog server for authentication. A global catalog server is an Active Directory domain controller that has been granted the Global Catalog (GC) role.
The global catalog is a partial representation of all objects from every domain within the Active Directory forest. The Vocera Voice Server can search Active Directory, but it does not need to refer to specific domain controllers that store the requested user data.
The default global catalog SSL port is 3269. If you decide to use a global catalog server, firewall rules must allow inbound traffic to port 3269 on the domain controller.
If you have only one domain, Microsoft recommends that you configure all domain controllers as global catalog servers.