Every Mac by default has an application called Contacts. Every macOS Server 5.4, running on High Sierra, has a service called Contacts. While the names might imply very different things that they do, you’ll be super-surprised that the two are designed to work with one another. The Contacts service is based on CardDAV, a protocol for storing contact information on the web, retrievable and digestible by client computers. However, there is a layer of database-driven obfuscation between the Contacts service and CardDAV. The Contacts service is also a conduit with which to read information from LDAP and display that information in the Contacts client, which is in a way similar to how the Global…