If you select LDAP/AD authentication, users whose credentials are stored in an external LDAP or AD server can log in to Harbor directly. In this case, you do not create user accounts in Harbor.
**IMPORTANT**: You can change the authentication mode from database to LDAP only if no local users have been added to the database. If there is at least one user other than `admin` in the Harbor database, you cannot change the authentication mode.
Because the users are managed by LDAP or AD, self-registration, creating users, deleting users, changing passwords, and resetting passwords are not supported in LDAP/AD authentication mode.
If you want to manage user authentication by using LDAP groups, you must enable the `memberof` feature on the LDAP/AD server. With the `memberof` feature, the LDAP/AD user entity's `memberof` attribute is updated when the group entity's `member` attribute is updated, for example by adding or removing an LDAP/AD user from the LDAP/AD group. This feature is enabled by default in Active Directory. For information about how to enable and verify `memberof` overlay in OpenLDAP, see [this technical note]( https://technicalnotes.wordpress.com/2014/04/19/openldap-setup-with-memberof-overlay/).
1. Log in to the Harbor interface with an account that has Harbor system administrator privileges.
1. Under **Administration**, go to **Configuration** and select the **Authentication** tab.
1. Use the **Auth Mode** drop-down menu to select **LDAP**.
1. Enter the address of your LDAP server, for example `ldaps://10.162.16.194`.
1. Enter information about your LDAP server.
- **LDAP Search DN** and **LDAP Search Password**: When a user logs in to Harbor with their LDAP username and password, Harbor uses these values to bind to the LDAP/AD server. For example, `cn=admin,dc=example.com`.
- **LDAP Base DN**: Harbor looks up the user under the LDAP Base DN entry, including the subtree. For example, `dc=example.com`.
- **LDAP Filter**: The filter to search for LDAP/AD users. For example, `objectclass=user`.
- **LDAP UID**: An attribute, for example `uid`, or `cn`, that is used to match a user with the username. If a match is found, the user's password is verified by a bind request to the LDAP/AD server.
- **LDAP Scope**: The scope to search for LDAP/AD users. Select from **Subtree**, **Base**, and **OneLevel**.