3.1.1.3.1.10 Ports
An AD DS DC accepts LDAP connections on the standard LDAP and LDAPS (LDAP over SSL/TLS) ports: 389 and 636. If the AD DS DC is a GC server, it also accepts LDAP connections for GC access on port 3268 and LDAPS connections for GC access on port 3269.
An AD LDS DC accepts LDAP and LDAPS connections on ports that are configured when creating the DC.