Service Virtualization

I need to double check if direct access from Devtest Workstation to LDAP/AD is mandatory. Customer is requesting info regarding the Ports they have to open (firewalls) in order to setup propertly DevTest commponents comunication. I am pretty sure that DevTest Worksation must have direct access to LDAP/AD but I need confirmation about this topic.

The connection to the LDAP server for authentication is done by the Registry, so the Workstation should not have to have a direct connection to the LDAP Server.