Amazon Linux 2023 の EC2 インスタンスに Postfix を user data を利用して自動構築してみた

#!/bin/bash
set -euxo pipefail
exec > >(tee /var/log/user-data-mailsetup.log | logger -t user-data -s 2>/dev/console) 2>&1
# ==========================================
# 変更値
# ==========================================
HOST_FQDN="mail.example.com"
MAIL_DOMAIN="example.com"
VPC_CIDR="10.0.0.0/16"
# ==========================================
# ホスト名設定
hostnamectl set-hostname "${HOST_FQDN}"
# パッケージ更新・導入
dnf -y update
dnf -y install postfix dovecot
dnf -y install telnet
# ------------------------------------------
# Postfix 設定
# ------------------------------------------
postconf -e "myhostname = ${HOST_FQDN}"
postconf -e "mydomain = ${MAIL_DOMAIN}"
postconf -e "myorigin = \$mydomain"
postconf -e "mydestination = \$myhostname, localhost.\$mydomain, localhost, \$mydomain"
postconf -e "mynetworks = ${VPC_CIDR}, 127.0.0.0/8"
postconf -e "smtpd_banner = \$myhostname ESMTP"
postconf -e "home_mailbox = Maildir/"
postconf -e "inet_interfaces = all"
postconf -e "inet_protocols = ipv4"
# SMTP AUTH (Dovecot 連携)
postconf -e "smtpd_sasl_auth_enable = yes"
postconf -e "smtpd_sasl_type = dovecot"
postconf -e "smtpd_sasl_path = private/auth"
postconf -e "smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination"
# submission (587) 有効化
sed -ri 's/^#submission inet /submission inet /' /etc/postfix/master.cf
sed -ri 's/^#  -o syslog_name=postfix\/submission/  -o syslog_name=postfix\/submission/' /etc/postfix/master.cf
sed -ri 's/^#  -o smtpd_tls_security_level=encrypt/  -o smtpd_tls_security_level=may/' /etc/postfix/master.cf
sed -ri 's/^#  -o smtpd_sasl_auth_enable=yes/  -o smtpd_sasl_auth_enable=yes/' /etc/postfix/master.cf
sed -ri 's/^#  -o smtpd_relay_restrictions=permit_sasl_authenticated,reject/  -o smtpd_relay_restrictions=permit_sasl_authenticated,reject/' /etc/postfix/master.cf
sed -ri 's/^#  -o milter_macro_daemon_name=ORIGINATING/  -o milter_macro_daemon_name=ORIGINATING/' /etc/postfix/master.cf
# ------------------------------------------
# Dovecot 設定
# ------------------------------------------
cat > /etc/dovecot/conf.d/99-mailserver.conf <<'EOF'
mail_location = maildir:~/Maildir
disable_plaintext_auth = no
auth_mechanisms = plain login
ssl = no
service auth {
  unix_listener /var/spool/postfix/private/auth {
    mode = 0666
    user = postfix
    group = postfix
  }
}
EOF
# ------------------------------------------
# サービス起動
# ------------------------------------------
postfix check
doveconf -n || true
systemctl enable --now postfix
systemctl enable --now dovecot
systemctl restart postfix
systemctl restart dovecot
systemctl status postfix --no-pager || true
systemctl status dovecot --no-pager || true
ss -lntp || true

hostnamectl
postconf | egrep '^(myhostname|mydomain|myorigin|mydestination|mynetworks|home_mailbox|smtpd_sasl_auth_enable)'
systemctl status postfix
systemctl status dovecot
ss -lntp | egrep ':25|:587|:143|:110'

sudo useradd -m mailuser
sudo passwd mailuser

sudo mkdir -p /home/mailuser/Maildir/{new,cur,tmp}
sudo chown -R mailuser:mailuser /home/mailuser/Maildir
sudo chmod -R 700 /home/mailuser/Maildir

sudo id mailuser
sudo ls -ld /home/mailuser
sudo ls -l /home/mailuser

sudo doveadm auth test mailuser

telnet localhost 25

helo localhost
mail from:mailuser@example.com
rcpt to:mailuser@example.com
data
This is test mail.
.
quit

sudo ls -l /home/mailuser/Maildir/new/
sudo cat /home/mailuser/Maildir/new/17xxxxxx.xxxxxxxxxxxxxxxx80850.xxxxx.test.xx.xxxxxxx.info

telnet localhost 110

USER mailuser
PASS 設定したパスワード
STAT
LIST
RETR 1
QUIT

telnet localhost 143

a login "mailuser" "設定したパスワード"
a select INBOX
a search all
a fetch 1 body[text]
a logout