Many thanks Manikandan,
I found also this query:
select SI_OWNER, SI_DESCRIPTION, SI_NAME, SI_AUTHEN_METHOD, SI_LOGON_ALIAS, SI_CREATION_TIME, SI_UPDATE_TS FROM CI_SYSTEMOBJECTS WHERE SI_KIND='Connection'
that is supposed to give me the current user connection list, but the data displayed refer in most of the cases to an enterprise connection, that is not coherent with the custom user addressing to BI configured in our system. I expect to see an ldap or server token or win AD authentication mode but I see secEnterprise in 99% of the logins. Do you have an explanation for this or should I trust this info and assume users are logging in through the enterprise mode?
Thanks again
Fab