I didn't thought of any specific LDAP server. It would be great to connect Cloudron to any external LDAP server, that would manage groups and users. For example, connect a Cloudron server to another one so that only one Cloudron server manages the users and groups for both servers.

There was some more discussion on this happening at https://git.cloudron.io/cloudron/box/issues/69 Short answer, we won't add this for now as apps use user groups in too many different ways and a mapping will be very complex and confusing.