Bon, j'ai trouvé, voici mon main.cf :
<BR>
<BR>#soft_bounce = no
<BR>command_directory = /usr/sbin
<BR>daemon_directory = /usr/lib/postfix
<BR>#default_privs = nobody
<BR>#myorigin = $myhostname
<BR>myorigin = mondomaine.com
<BR>#inet_interfaces = $myhostname
<BR>#inet_interfaces = $myhostname, localhost
<BR>#proxy_interfaces =
<BR>#proxy_interfaces = 1.2.3.4
<BR>mydestination = $myhostname, localhost.$mydomain, $mydomain
<BR>#mydestination = $myhostname, localhost.$mydomain $mydomain
<BR>#mydestination = $myhostname, localhost.$mydomain, $mydomain,
<BR># mail.$mydomain,
www.$mydomain, ftp.$mydomain
<BR>#local_recipient_maps = unix:passwd.byname $alias_maps
<BR>#local_recipient_maps = proxy:unix:passwd.byname $alias_maps
<BR>#local_recipient_maps =
<BR>#unknown_local_recipient_reject_code = 550
<BR>unknown_local_recipient_reject_code = 450
<BR>#mynetworks_style = class
<BR>#mynetworks_style = subnet
<BR>#mynetworks_style = host
<BR>mynetworks = ma classe IP, 127.0.0.0/8
<BR>#mynetworks = $config_directory/mynetworks
<BR>#mynetworks = hash:/etc/postfix/network_table
<BR>#relayhost = gateway.my.domain
<BR>#relayhost = uucphost
<BR>#relayhost = [an.ip.add.ress]
<BR>#relay_recipient_maps = hash:/etc/postfix/relay_recipients
<BR>#in_flow_delay = 1s
<BR>#alias_maps = dbm:/etc/aliases
<BR>alias_maps = hash:/etc/postfix/aliases
<BR>#alias_maps = hash:/etc/aliases, nis:mail.aliases
<BR>#alias_maps = netinfo:/aliases
<BR>#alias_database = dbm:/etc/aliases
<BR>#alias_database = dbm:/etc/mail/aliases
<BR>#alias_database = hash:/etc/aliases
<BR>#alias_database = hash:/etc/aliases, hash:/opt/majordomo/aliases
<BR>#recipient_delimiter = +
<BR>#home_mailbox = Mailbox
<BR>#home_mailbox = Maildir/
<BR>#mail_spool_directory = /var/mail
<BR>mail_spool_directory = /var/spool/mail
<BR>#mailbox_command = /some/where/procmail
<BR>#mailbox_command = /some/where/procmail -a "$EXTENSION"
<BR>mailbox_command = /usr/bin/procmail -Y -a $DOMAIN
<BR>#mailbox_transport = lmtp:unix:/file/name
<BR>#mailbox_transport = cyrus
<BR>#luser_relay = $user@other.host
<BR>#luser_relay = $local@other.host
<BR>#luser_relay = admin+$local
<BR>#header_checks = regexp:/etc/postfix/header_checks
<BR>#fast_flush_domains = $relay_domains
<BR>#fast_flush_domains =
<BR>#smtpd_banner = $myhostname ESMTP $mail_name
<BR>#smtpd_banner = $myhostname ESMTP $mail_name ($mail_version)
<BR>smtpd_banner = $myhostname ESMTP $mail_name ($mail_version) (Mandrake Linux)
<BR>#local_destination_concurrency_limit = 2
<BR>#default_destination_concurrency_limit = 10
<BR>debug_peer_level = 2
<BR>#debug_peer_list = 127.0.0.1
<BR>#debug_peer_list = some.domain
<BR>debugger_command =
<BR> PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
<BR> xxgdb $daemon_directory/$process_name $process_id & sleep 5
<BR>delay_warning_time = 4
<BR>sendmail_path = /usr/sbin/sendmail.postfix
<BR>newaliases_path = /usr/bin/newaliases.postfix
<BR>mailq_path = /usr/bin/mailq.postfix
<BR>setgid_group = postdrop
<BR>manpage_directory = /usr/share/man
<BR>sample_directory = /usr/share/doc/postfix-2.0.6/samples
<BR>readme_directory = /usr/share/doc/postfix-2.0.6/README_FILES
<BR>alias_database = hash:/etc/postfix/aliases
<BR>smtpd_recipient_restrictions =
<BR> check_sender_access hash:/etc/postfix/restricted_senders
<BR> permit_mynetworks
<BR> reject_unauth_destination
<BR>smtpd_restriction_classes = local_only
<BR>local_only = check_recipient_access hash:/etc/postfix/local_domains, reject
<BR>
<BR>dans etc/postfix/restricted_senders, j'ai mes utilisateurs limités au local et dans /etc/postfix/local_domains les domaines locaux.
<BR>
<BR>ça marche !
<BR>
<BR>