newbies help

[adri <adriano.archetti@tiscali.it>]

i'm really new from ldap, but i think it's a really good instrument, so
i wanna configure my addressbook, initially, with ldap.
i have a doubt, i search to add the mail entry at a user, but the server
answer me:

ldif_record() = 68
adding new entry "cn=Username, ou=Addressbook, o=rubrica, c=IT"
ldap_add: Undefined attribute type
        additional info: Email: attribute type undefined

i think this is a problem about cn or objectClass.
my question it's really simple, what objectClass i have to insert in my
ldif file to insert "mail".
this are my files:

*******************************
slapd.conf
*******************************
include         /etc/openldap/schema/core.schema
include         /etc/openldap/schema/cosine.schema
include         /etc/openldap/schema/inetorgperson.schema
include         /etc/openldap/schema/nis.schema
include         /etc/openldap/schema/misc.schema
include         /etc/openldap/schema/openldap.schema
index cn,sn,uid,o,c,ou,dn
index objectClass
pres,eq,person,organization,organizationalunit,addressbook
database ldbm
suffix   "o=rubrica, c=IT"
rootdn   "cn=user, o=rubrica, c=IT"
rootpw <myrootpw>
directory       /var/lib/ldap/

*******************************
user.ldif
*******************************
dn: o=rubrica, c=IT
o: rubrica
objectClass: organization
description:La mia organizzazione

dn: ou=Addressbook, o=rubrica, c=IT
ou: Addressbook
objectClass: organizationalUnit

dn: ou=Users, o=rubrica, c=IT
ou: Users
objectClass: organizationalUnit

dn: cn=Username, ou=Addressbook, o=rubrica, c=IT
cn: Username
telephoneNumber: 1234567890
mail:themail@mail.it
objectClass: person
objectClass: organizationalPerson
description: Questo sono io

many thanks
adri
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