Active Directory communication takes place using several ports. These ports are required by both client computers and Domain Controllers. As an example, when a client computer tries to find a domain controller it always sends a DNS Query over Port 53 to find the name of the domain controller in the domain.
The following is the list of services and their ports used for Active Directory communication:
Opening above ports in Firewall between client computers and domain controllers, or between domain controllers, will enable Active Directory to function properly