apt install postfix mailutils libsasl2-modules
postfix = MTA
mailutils = cli mail
libsasl2-modules = SASL authentication modules
nano /etc/postfix.main.cf
# See /usr/share/postfix/main.cf.dist for a commented, more complete version
# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on
# fresh installs.
compatibility_level = 2
# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_security_level=may
smtp_tls_CApath=/etc/ssl/certs
smtp_tls_security_level=may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = nom_proxmox
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = $myhostname, localhost.localdomain, , localhost
#relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all
smtp_use_tls=yes
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtp_sasl_tls_security_options = noanonymous
tls_random_source = dev:/dev/urandom
smtp_sasl_auth_enable = yes
relayhost=[ip/dns serveur mail]:465
smtp_sasl_password_maps=hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
nano /etc/postfix/sasl_passwd
[ip/dns serveur]:465 user:********************
postmap /etc/postfix/sasl_passwd
Changez le propriétaire en root et les permissions de fichiers en 600
chown root:root /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
chmod 0600 /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
Recharger postfix
postfix reload
echo "this is a test email" | mail -s "test email" adresse_destination"