Não há motivo para você usar qualquer software externo na maioria das distribuições.
Para o Debian / Ubuntu, você pode fazer isso com libnss-ldap e libpam-krb5. Existem alguns truques para obtê-lo 100%. Isso pressupõe que você tenha "unixHomeDirectory" preenchido para usuários do Linux, suas caixas Linux estejam usando o NTP comum com seus sistemas Windows (exigido pelo Kerberos) e que você esteja bem com pesquisas em NSS em texto sem formatação (não senha, mas informações de associação ao grupo etc. - você também pode use TLS, mas é mais complicado de configurar). Você NÃO deve ter o pam_ldap como uma senha ou fonte de autenticação no PAM, a menos que esteja configurado para usar o TLS.
/etc/ldap.conf
# LDAP Configuration for libnss-ldap and libpam-ldap.
# Permit host to continue boot process with out contacting LDAP server
bind_policy soft
# Define LDAP servers to use for queries, these must be Global Catalog servers
uri ldap://ldap.site.company.local
# Define root search location for queries
base dc=company,dc=local
#debug 1
# LDAP version, almost always going to be v3, it is quite mature
ldap_version 3
# Username used to proxy authentication. You can have this in a separate file owned by root for security OR use TLS/SSL (see man page)
# Do NOT use LDAP for authentication if you are using plain text binds, use Kerberos instead (and LDAP for authorization only). See libpam-krb5.
binddn cn=ldap-auth-svc,ou=ldap,ou=services,dc=site,dc=company,dc=local
# Password for proxy acct
bindpw SooperSekeretPazzwerd
# TCP port to perform queries on, 3268 is a Global Catalog port which will reply for all users in *.company.local
port 3268
# Search range scope (sub = all)
scope sub
# Tell the client to close TCP connctions after 30 seconds, Windows will do this on the server side anyways, this will prevent errors from showing up in the logs.
idle_timelimit 30
# Expect queries for group membership to return DN for group members instead of usernames (lets you use MSAD group membership seamlessly)
nss_schema rfc2307bis
# Filters - User accounts must have a UID >= 2000 to be recognized in this configuration and must have a unixHomeDirectory defined.
nss_base_group dc=company,dc=local?sub?&(objectClass=group)(gidNumber=*)
nss_base_user dc=company,dc=local?sub?&(objectClass=user)(!(objectClass=localputer))(uidNumber>=2000)(unixHomeDirectory=*)
nss_base_shadow dc=company,dc=local?sub?&(objectClass=user)(!(objectClass=localputer))(uidNumber>=2000)(unixHomeDirectory=*)
# Object Class mappings. You may want to have the posixAccount to map to "mail" and have users login with their email addresses, i.e. "nss_map_objectclass posixAccount mail".
nss_map_objectclass posixAccount user
nss_map_objectclass shadowAccount user
nss_map_objectclass posixGroup group
# Attribute mappings.
nss_map_attribute uniqueMember member
nss_map_attribute uid sAMAccountName
nss_map_attribute homeDirectory unixHomeDirectory
nss_map_attribute shadowLastChange pwdLastSet
# Attribute in LDAP to query to match the username used by PAM for authentication
pam_login_attribute sAMAccountName
# Filter for objects which are allowed to login via PAM
pam_filter objectclass=User
Não é necessário editar o arquivo /etc/krb5.conf, supondo que suas caixas Linux estejam usando servidores DNS que conhecem o AD (as zonas _msdcs com os registros SRV apropriados são resolvíveis)
O arquivo /etc/nsswitch.conf deve ter "arquivos ldap" para usuários, grupos e sombra.
Para o Red Hat usando SSSD:
/etc/sssd/sssd.conf
[domain/AD]
id_provider = ldap
auth_provider = krb5
chpass_provider = krb5
access_provider = ldap
ldap_uri = ldap://ldap.company.local:3268/
ldap_search_base = dc=company,dc=com
ldap_default_bind_dn = cn=ldap-auth-svc,ou=ldap,ou=services,dc=site,dc=company,dc=local
ldap_default_authtok = SooperSekeretPazzwerd
ldap_schema = rfc2307bis
ldap_user_object_class = user
ldap_group_object_class = group
ldap_user_name = sAMAccountName
ldap_user_home_directory = unixHomeDirectory
enumerate = true
ldap_tls_reqcert = never
ldap_tls_cacertdir = /etc/openldap/cacerts
ldap_id_use_start_tls = False
cache_credentials = True
krb5_realm = SITE.COMPANY.COM
case_sensitive = false
[sssd]
services = nss, pam
config_file_version = 2
domains = AD
[nss]
filter_users = root,named,avahi,nscd