Directory Services Screens
The Directory Services screen and widgets provide access to TrueNAS settings to set up access to directory services and advanced authentication systems deployed in user environments.
TrueNAS does not configure Active Directory domain controllers or LDAP directory servers, nor does it configure Kerberos authentication servers or ID mapping systems.
Refer to documentation for these services and systems for information on how to configure each to suit your use case.
Idmap Screens
Idmap in Linux is essentially a translation of a range of IDs into another or the same range of IDs.
Only administrators experienced with configuring Id mapping should attempt to add new or edit existing idmaps. Misconfiguration can impact system operation.The Idmap widget in the Advanced Settings on the Directory Services screen displays idmaps added to TrueNAS.
Configuring IDMap
Idmap settings exist for the purpose of integration with an existing directory domain to ensure that UIDs and GIDs assigned to Active Directory users and groups have consistent values domain-wide. The correct configuration therefore relies on details that are entirely external to the TrueNAS server, e.g., how the AD administrator has configured other Unix-like computers in the environment.
The default is to use an algorithmic method of generating IDs based on the RID component of the user or group SID in Active Directory.