Hello everybody, I have had some problems about to authorize users based on Active Directory (Samba 4 DCs) groups. I have followed http://deployingradius.com/documents/configuration/active_directory.html to configure ntlm_auth and it works perfectly. As I need restrict access to some AD groups, I need to configure ldap module. I've alright configured ldap module, but it has been pure Openldap (uid stores username and usePassword stores password). Then, to set up ldap module to access AD ldap, I've read comments on mods-available/ldap and I have set up "server", "identity", "password" and "base_dn" on the mods-enabled/ldap. I have also set up to use the attribute stores username on AD user { ... filter = "(sAMAccountName=%{%{Stripped-User-Name}:-%{User-Name}})" ... } and group { ... filter = '(objectClass=group)' ... name_attribute = cn membership_filter = "(|(member=%{control:Ldap-UserDn})(memberUid=%{%{Stripped-User-Name}:-%{User-Name}}))" membership_attribute = 'memberOf' ... } When I have tried to run radiusd -X, it has shown a error message about bind tried to ldap server: rlm_ldap (ldap): Opening additional connection (0), 1 of 32 pending slots used rlm_ldap (ldap): Connecting to ldap://dc01.mydomain.com:389 rlm_ldap (ldap): Waiting for bind result... rlm_ldap (ldap): Bind with cn=Administrator,cn=Users,dc=mydomain,dc=com to ldap://dc01.mydomain.com:389 failed: Strong(er) authentication required rlm_ldap (ldap): Server said: BindSimple: Transport encryption required.. rlm_ldap (ldap): Opening connection failed (0) rlm_ldap (ldap): Removing connection pool /etc/raddb/mods-enabled/ldap[8]: Instantiation failed for module "ldap" I've suspected about SASL due I haven't been notify that LDAP use STARTTLS or SSL over TLS. Then I've commented identity and password and radiusd -X rlm_ldap (ldap): Opening additional connection (0), 1 of 32 pending slots used rlm_ldap (ldap): Connecting to ldap://dc01.mydomain.com:389 rlm_ldap (ldap): Starting SASL mech(s): GSSAPI SASL/GSSAPI authentication started rlm_ldap (ldap): Bind with (anonymous) to ldap://dc01.mydomain.com:389 failed: Local error rlm_ldap (ldap): Opening connection failed (0) rlm_ldap (ldap): Removing connection pool /etc/raddb/mods-enabled/ldap[8]: Instantiation failed for module "ldap" I run kinit Administrator before run the ldapsearch below and hasn't shown any ERROR. Please, can someone help me about my problem? [root@centos8 ~]# ldapsearch -LLL -h dc01.mydomain.com -b "ou=drc,dc=mydomain,dc=com" sAMAccountName SASL/GSS-SPNEGO authentication started SASL username: Administrator@MYDOMAIN.COM SASL SSF: 256 SASL data security layer installed. -- Igor Sousa