It’s possible to use a LDAP server as backend server for user authentication.
The only Local EAP methods that are supported are :
EAP-TLS, EAP-FAST/GTC, PEAP/GTC.
LEAP, EAP-FAST/MSCHAPv2 and PEAPv0/MSCHAPv2 are only supported when the LDAP servier returns clear-text passwords. The Microsoft LDAP server doesn’t return clear-text passwords.
If the LDAP server is reachable, but the user is unknown, then the authentication will be rejected.
If the LDAP server is unreachable, the local database will be used.