سرور ایمیل با Postfix و Dovecot: ارسال امن، IMAP و رکوردهای SPF، DKIM و DMARC

mail.sahor.ir.        A     203.0.113.10
sahor.ir.             MX 10 mail.sahor.ir.
sahor.ir.             TXT   "v=spf1 mx -all"
_dmarc.sahor.ir.      TXT   "v=DMARC1; p=quarantine; rua=mailto:dmarc@sahor.ir"

sudo hostnamectl set-hostname mail.sahor.ir
sudo apt install -y certbot
sudo certbot certonly --standalone -d mail.sahor.ir

sudo apt install -y postfix   # choose "Internet Site", system mail name: sahor.ir

sudo postconf -e 'myhostname = mail.sahor.ir'
sudo postconf -e 'mydomain = sahor.ir'
sudo postconf -e 'myorigin = $mydomain'
sudo postconf -e 'mydestination = $myhostname, $mydomain, localhost'
sudo postconf -e 'home_mailbox = Maildir/'
sudo postconf -e 'smtpd_tls_cert_file = /etc/letsencrypt/live/mail.sahor.ir/fullchain.pem'
sudo postconf -e 'smtpd_tls_key_file = /etc/letsencrypt/live/mail.sahor.ir/privkey.pem'
sudo postconf -e 'smtpd_tls_security_level = may'
sudo postconf -e 'smtp_tls_security_level = may'
sudo postconf -e 'smtpd_sasl_type = dovecot'
sudo postconf -e 'smtpd_sasl_path = private/auth'
sudo postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination'
sudo postconf -e 'message_size_limit = 26214400'

submission inet n       -       y       -       -       smtpd
  -o syslog_name=postfix/submission
  -o smtpd_tls_security_level=encrypt
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_client_restrictions=permit_sasl_authenticated,reject

sudo apt install -y dovecot-imapd dovecot-lmtpd

mail_location = maildir:~/Maildir
ssl = required
ssl_cert = </etc/letsencrypt/live/mail.sahor.ir/fullchain.pem
ssl_key = </etc/letsencrypt/live/mail.sahor.ir/privkey.pem
ssl_min_protocol = TLSv1.2
disable_plaintext_auth = yes
auth_mechanisms = plain login

service auth {
  unix_listener /var/spool/postfix/private/auth {
    mode = 0660
    user = postfix
    group = postfix
  }
}

sudo doveconf -n >/dev/null && sudo systemctl restart dovecot postfix
sudo ufw allow 25,587,993/tcp

sudo apt install -y opendkim opendkim-tools
sudo mkdir -p /etc/opendkim/keys/sahor.ir
sudo opendkim-genkey -b 2048 -d sahor.ir -s mail -D /etc/opendkim/keys/sahor.ir
sudo chown -R opendkim:opendkim /etc/opendkim
sudo cat /etc/opendkim/keys/sahor.ir/mail.txt     # publish as TXT mail._domainkey.sahor.ir

Domain    sahor.ir
Selector  mail
KeyFile   /etc/opendkim/keys/sahor.ir/mail.private
Socket    inet:8891@127.0.0.1

sudo postconf -e 'smtpd_milters = inet:127.0.0.1:8891'
sudo postconf -e 'non_smtpd_milters = $smtpd_milters'
sudo postconf -e 'milter_default_action = accept'
sudo systemctl restart opendkim postfix

sudo adduser --shell /usr/sbin/nologin ali
echo "test body" | mail -s "test" ali@sahor.ir     # needs: apt install mailutils
sudo ls /home/ali/Maildir/new/