[Samba] Samba-Tool setup default passwd db type?

[Greg Zartman]

I'm working to setup a Samba 4 AD DC and ran through the howto on the wiki.
  https://wiki.samba.org/index.php/Samba_AD_DC_HOWTO

What type of database backend is Samba using?  Is it using the LDAP server
internal to Samba or a tdb database?

The man page for smb.conf says that the default passdb backend is tdb, so I
was curious what Samba-Tool is going.

Thanks,

-- 
Greg