[Samba] Linux client of the domain

[Cyril]

Hello,

I think I'm starting to understand how Linux client can be integrated 
into a samba domain.

Tell me if I'm wrong :

Linux clients don't need Samba for authentication, only the ldap part of 
samba.
sssd through kerberos get information from ldap. If the user is known or 
get the right, he can log.

So why should I need to install winbind and samba4 on the linux client ?
Is it only if I have a Windows AD ?


Thanks
Cyril