need some information

["Mruga" <mruganayana@hotmail.com>]

Hi,

I am new to LDAP and wanted some information.
(my questions are based on limited understanding).

- openldap implements both a LDAP client and a server, but
does it implement a X.500 directory ?
- apart from Active Directory, are there any other directory
implementations ?
- suppose, I have to use LDAP for user authentication on Unix
systems, do I have to use Kerberos (if I don't want to use simple
passwords) ? where would be the user information stored in this
case ?

regards
mruga