Устанавливаем необходимые пакеты

apt-get update
apt-get install libnss-ldap

Отвечаем на вопросы

Если вы пропустили настройку во время установки - забейте, все равно проще ручками поправить конфиги!

Правим файл конфигурации /etc/ldap.conf

# Your LDAP server. Must be resolvable without using LDAP.
# Multiple hosts may be specified, each separated by a 
# space. How long nss_ldap takes to failover depends on
# whether your LDAP client library supports configurable
# network or connect timeouts (see bind_timelimit).
host 127.0.0.1
 
# The distinguished name of the search base.
base dc=drivesource,dc=ru
 
# The LDAP version to use (defaults to 3
# if supported by client library)
ldap_version 3
 
# Reconnect policy: hard (default) will retry connecting to
# the software with exponential backoff, soft will fail
# immediately.
bind_policy soft
 
# Filter to AND with uid=%s
#pam_filter objectclass=account
pam_filter objectClass=posixAccount
 
# The user ID attribute (defaults to uid)
pam_login_attribute uid
 
# Group member attribute
pam_member_attribute memberUid
 
# Do not hash the password at all; presume
# the directory server will do it, if
# necessary. This is the default.
pam_password exop
 
# RFC2307bis naming contexts
# Syntax:
# nss_base_XXX          base?scope?filter
# where scope is {base,one,sub}
# and filter is a filter to be &'d with the
# default filter.
# You can omit the suffix eg:
# nss_base_passwd       ou=People,
# to append the default base DN but this
# may incur a small performance impact.
nss_base_passwd ou=Users,dc=drivesource,dc=ru?one
nss_base_shadow ou=Users,dc=drivesource,dc=ru?one
nss_base_group ou=Groups,dc=drivesource,dc=ru?one

Правим файл конфигурации /etc/nsswitch.conf

passwd:         compat ldap
group:          compat ldap
shadow:         compat ldap