In order to use LDAP authentication in Nexus, you will need to add the Nexus LDAP Authentication Realm to the Selected Realms in the Security section of the Server configuration panel. To load the Server configuration panel, click on the Server link under Administration in the Nexus menu. Once you have the Server configuration panel loaded, select Enterprise LDAP Authentication Realm (or OSS LDAP Authentication Realm) in the Available Realms list under the Security section and click the Add button (or Left Arrow) as shown in Figure 8.1, “Adding the LDAP Authentication Realm to Available Realms” and ensure that the LDAP realm is located below the XML realms in the list.
This is necessary, so that Nexus can be used by anonymous, admin and other users configured in the XML realms even with LDAP authentication offline or unavailable. Any user account not found in the XML realms, will be passed through to LDAP authentication.
Next, click on the Save button at the bottom of the Server configuration panel to have the change applied.