Смотрим название node:
hostname -f
nano /etc/postfix/main.cf
myhostname = proxmox-name.piksrv.ru
mydomain = piksrv.ru
myorigin = /etc/mailname
inet_interfaces = all
inet_protocols = ipv4
mydestination = $myhostname, localhost.$mydomain, localhost
compatibility_level = 3.6
relayhost = [smtp.mail.ru]:465
smtp_use_tls = yes
smtp_tls_wrappermode = yes
smtp_tls_security_level = encrypt
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_generic_maps = hash:/etc/postfix/generic
header_checks = pcre:/etc/postfix/rewrite_subject
*******************************************************************
nano /etc/postfix/sasl_passwd
[smtp.mail.ru]:465 info@piksrv.ru:Сюда пишем свой пароль
*******************************************************************
nano /etc/postfix/generic
root@proxmox-name.piksrv.ru info@piksrv.ru
root info@piksrv.ru
*******************************************************************
nano /etc/aliases
root: info@piksrv.ru
*******************************************************************
nano /etc/postfix/rewrite_subject
/^Subject: (.*)$/ REPLACE Subject: [proxmox-name.piksrv.ru]: $1
*******************************************************************
nano /etc/mailname
proxmox-name.piksrv.ru
*******************************************************************
postmap /etc/postfix/generic
postmap /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
postfix check
systemctl restart postfix
systemctl status postfix --no-pager
*******************************************************************
echo "Test email body" | mail -s "Test Subject" test@mail.ru
printf "Subject: test2\n\nhello\n" | sendmail -v test@mail.ru
*******************************************************************
tail -f /var/log/mail.log
journalctl -u postfix --since "5 minutes ago" --no-pagern
#postfix #proxmox #mail.ru