Salut ,

Par defaut , postfix est paramétré pour éviter de fonctionner en open relay
Grace à mynetworks .
Ensuite pour eliminer du spam , tu peux dans un premier temps utiliser les rbl , et autres régles dans :
smtpd_recipient_restrictions

Puis pour enlever encore 90% de spam , utiliser une greylist ... déprécié par certains .. perso je trouve ca bien ...

Et enfin , tu peux utiliser spamassassin , clamav (pour les virus) , amavisd-new , DCC , razor ...

Pour t'aider à commencer :

http://memo.lindev.fr/index.php?categorie=4

Mon memo: foxblog.dsl-fr.eu
Une de mes réalisations :

Postconf -n :

alias_database = hash:/usr/local/etc/postfix/aliases
alias_maps = hash:/etc/aliases
config_directory = /etc/postfix
html_directory = no
inet_interfaces = all
mail_owner = postfix
mailbox_size_limit = 0
mailq_path = /usr/local/bin/mailq
mydestination = servmail, localhost.localdomain, localhost
mydomain = $myhostname
myhostname = ***.dyndns.org
mynetworks = 127.0.0.0/8 10.0.0.0/24 10.0.4.0/24 ***.252.**.59/32 ***.252.***.101/32 ***.167.**.143/32
mynetworks_style = host
myorigin = $myhostname
newaliases_path = /usr/local/bin/newaliases
readme_directory = no
recipient_delimiter = +
relay_domains = $mydestination
relayhost = smtp.orange.fr
sendmail_path = /usr/local/sbin/sendmail
smtp_tls_session_cache_database = btree:${queue_directory}/smtp_scache
smtpd_sender_login_maps = mysql:/usr/local/etc/postfix/mysql_virtual_sender.cf
smtpd_tls_cert_file = /etc/postfix/smtpd.cert
smtpd_tls_key_file = /etc/postfix/smtpd.key
smtpd_tls_session_cache_database = btree:${queue_directory}/smtpd_scache
smtpd_use_tls = yes
unknown_local_recipient_reject_code = 550
virtual_alias_maps = mysql:/usr/local/etc/postfix/mysql_virtual_alias_maps.cf
virtual_gid_maps = static:120
virtual_mailbox_base = /usr/local/virtual
virtual_mailbox_domains = mysql:/usr/local/etc/postfix/mysql_virtual_domains_maps.cf
virtual_mailbox_limit = 51200000
virtual_mailbox_maps = mysql:/usr/local/etc/postfix/mysql_virtual_mailbox_maps.cf
virtual_minimum_uid = 100
virtual_transport = virtual
virtual_uid_maps = static:109


Pour le master.cf:

smtp inet n - - - - smtpd
#submission inet n - - - - smtpd
# -o smtpd_enforce_tls=yes
# -o smtpd_sasl_auth_enable=yes
# -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#smtps inet n - - - - smtpd
# -o smtpd_tls_wrappermode=yes
# -o smtpd_sasl_auth_enable=yes
# -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#628 inet n - - - - qmqpd
pickup fifo n - - 60 1 pickup
cleanup unix n - - - 0 cleanup
qmgr fifo n - n 300 1 qmgr
#qmgr fifo n - - 300 1 oqmgr
tlsmgr unix - - - 1000? 1 tlsmgr
rewrite unix - - - - - trivial-rewrite
bounce unix - - - - 0 bounce
defer unix - - - - 0 bounce
trace unix - - - - 0 bounce
verify unix - - - - 1 verify
flush unix n - - 1000? 0 flush
proxymap unix - - n - - proxymap
smtp unix - - - - - smtp
# When relaying mail as backup MX, disable fallback_relay to avoid MX loops
relay unix - - - - - smtp
-o smtp_fallback_relay=
# -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq unix n - - - - showq
error unix - - - - - error
retry unix - - - - - error
discard unix - - - - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - - - - lmtp
anvil unix - - - - 1 anvil
scache unix - - - - 1 scache
# ============================================================­========
# Interfaces to non-Postfix software. Be sure to examine the manual
# pages of the non-Postfix software to find out what options it wants.
#
# Many of the following services use the Postfix pipe(8) delivery
# agent. See the pipe(8) man page for information about ${recipient}
# and other message envelope options.
# ============================================================­========
#
# maildrop. See the Postfix MAILDROP_README file for details.
# Also specify in main.cf: maildrop_destination_recipient_limit=1
#
maildrop unix - n n - - pipe
flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
#
# See the Postfix UUCP_README file for configuration details.
#
uucp unix - n n - - pipe
flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
#
# Other external delivery methods.
#
ifmail unix - n n - - pipe
flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp unix - n n - - pipe
flags=Fq. user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix - n n - 2 pipe
flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop} ${user} ${extension}
mailman unix - n n - - pipe
flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
${nexthop} ${user}


Et pour la commande postmap transport

postfix/postmap[18580]: fatal: open transport: No such file or directory

Finalement ça n'intéresse plus personne ?
:(