I saw that by CSV I have to have specific fields like first name, last name, email ,,,, in LDAP I have to have these fields like that too?

I think you are talking about two totally different things:

LDAP is to provide access for survey administrators to the backend of Limesurvey.

The CSV upload is for when you use tokens (for survey takes, not survey creators).

No, you can import participant from an ldap request.

This ldap request must be inside in this php file

You have information about firstname/lastname and email .

And same for attributes

so isn't it for every network user to have intranet access? by AD?

Yes Yes
I want ldap to authenticate the participants without having to use tokne..ja would be the intranet access credential .... entered and would already be released

creocatia3d wrote: Yes Yes
I want ldap to authenticate the participants without having to use tokne..ja would be the intranet access credential .... entered and would already be released

No, it's import via an LDAP request.

It's not an LDAP particpant Authentification.

For such system : need to construct a plugin using www.limesurvey.org/manual/BeforeRegisterForm and www.limesurvey.org/manual/BeforeRegister

It's not included in LimeSurvey core.