Because the focus of this module is to use LDAP for networked authentication (to replace local files /etc/passwd, /etc/group and /etc/shadow), we will focus on the object classes specific to this purpose.
The core schema that we need for this purpose is the NIS schema. On a debian system, the schema can be found at /etc/ldap/schema/nis.schema. This file defines all the object classes and attribute types necessary to create entries that mirror the purposes of the local files passwd, group and shadow. Note that since we are using Kerberos for authentication, the passwords won’t be stored in LDAP.
When LDAP is installed in Debian, all the necessary schemas are also installed. These schemas are core, cosine, nis and inetorgperson.