A server certificate will be need for encrypted communication through Transport Layer Security (TLS).
Server Certificates
A server certificate serves to uniquely identify a server. The certificate must have been issued to the Fully Qualified Domain Name (FQDN) for the server. The server certificate must have been issued by a trusted authority. Certificates are configured from the Microsoft Management Console (MMC)'s Certificate Snap-in.
Certificate Storage
The certificates in use must be stored in the Local Computer / Personal storage area and contain a private key. Open the Local Computer storage area using the MMC console.
Version MetaDirectory_3.5