$ postconf -n
alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
allow_min_user = no
allow_percent_hack = no
biff = no
body_checks = pcre:/etc/postfix/body_checks.pcre
command_directory = /usr/sbin
compatibility_level = 3.6
content_filter = smtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/lib/postfix/sbin
data_directory = /var/lib/postfix
debug_peer_level = 2
disable_vrfy_command = yes
dovecot_destination_recipient_limit = 1
enable_long_queue_ids = yes
enable_original_recipient = no
header_checks = pcre:/etc/postfix/header_checks
inet_interfaces = all
inet_protocols = ipv4
lmtp_tls_mandatory_protocols = !SSLv2 !SSLv3 !TLSv1 !TLSv1.1
lmtp_tls_protocols = !SSLv2 !SSLv3 !TLSv1 !TLSv1.1
mail_owner = postfix
mailq_path = /usr/bin/mailq
message_size_limit = 15728640
...（输出节选：iRedMail 追加段还有 virtual_mailbox_domains/mysql 查询、mynetworks、TLS、sasl 等，全文以 postconf -n 为准）

$ grep -E '^(smtp|submission|amavis|dovecot|mlmmj)' -A 5 /etc/postfix/master.cf | head -42
smtp      inet  n       -       y       -       1       postscreen
smtpd     pass  -       -       y       -       -       smtpd
dnsblog   unix  -       -       y       -       0       dnsblog
tlsproxy  unix  -       -       y       -       0       tlsproxy
# Choose one: enable submission for loopback clients only, or for any client.
#127.0.0.1:submission inet n -   y       -       -       smtpd
#submission inet n       -       y       -       -       smtpd
--
submission inet  n       -       n       -       -       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
    -o content_filter=smtp-amavis:[127.0.0.1]:10026
--
dovecot    unix  -       n       n       -       -       pipe flags=DRh
    user=vmail:vmail argv=/usr/lib/dovecot/deliver -f ${sender} -d
    ${user}@${domain} -m ${extension}

# Amavisd integration.
mlmmj      unix  -       n       n       -       -       pipe flags=ORhu
--
smtp-amavis unix -       -       n       -       32      smtp
    -o syslog_name=postfix/amavis
    -o local_header_rewrite_clients=
    -o smtp_data_done_timeout=1200
    -o smtp_send_xforward_command=yes
    -o smtp_dns_support_level=disabled

$ ls /etc/postfix/mysql/
catchall_maps.cf       domain_alias_catchall.cf  recipient_bcc_maps.cf  sender_bcc_maps.cf  virtual_mailbox_maps.cf
relay_domains.cf       sender_login_maps.cf      virtual_alias_maps.cf  virtual_mailbox_domains.cf

$ grep -E '^!include|^protocols|^listen|^mail_location|^disable_plaintext_auth' /etc/dovecot/dovecot.conf
listen = *
protocols = pop3 imap sieve lmtp
disable_plaintext_auth = yes
mail_location = maildir:%Lh/Maildir/:INDEX=%Lh/Maildir/
!include conf.d/*.conf
!include_try /etc/dovecot/iredmail/*.conf

$ ls /etc/dovecot/
conf.d
dovecot-dict-auth.conf.ext
dovecot-dict-sql.conf.ext
dovecot-last-login.conf
dovecot-master-users
dovecot-mysql.conf
dovecot-share-folder.conf
dovecot-sql.conf.ext
dovecot-used-quota.conf
dovecot.conf

Admin of domain example.com:

    * Account: postmaster@example.com
    * Password: q1w2e3r4

SSL cert keys (size: 4096):
    - /etc/ssl/certs/iRedMail.crt
    - /etc/ssl/private/iRedMail.key

Mail Storage:
    - Mailboxes: /var/vmail/vmail1
    - Global sieve filters: /var/vmail/sieve
    - Backup scripts and backup copies: /var/vmail/backup

MySQL:
    * Root user: root, Password: "q1w2e3r4" (without quotes)
    * Bind account (read-only):
        - Username: vmail, Password: <安装时随机生成>
    * Vmail admin account (read-write):
        - Username: vmailadmin, Password: <安装时随机生成>
    * Config file: /etc/mysql/my.cnf

Backup MySQL database:
    * Script: /var/vmail/backup/backup_mysql.sh

Postfix:
    * Configuration files:
        - /etc/postfix
    * SQL/LDAP lookup config files:
        - /etc/postfix/mysql

Dovecot:
    * Configuration files:
        - /etc/dovecot/dovecot.conf

$ grep -E "^export (STORAGE|WEB_SERVER|BACKEND|USE_)" /root/iRedMail-1.7.4/config | head -8
export STORAGE_BASE_DIR='/var/vmail'
export WEB_SERVER='NGINX'
export BACKEND_ORIG='MARIADB'
export BACKEND='MYSQL'
export USE_IREDADMIN='YES'
export USE_ROUNDCUBE='YES'
export USE_NETDATA='YES'
export USE_FAIL2BAN='YES'

$ ls /opt/www/
iRedAdmin-2.6        iredadmin        roundcubemail        roundcubemail-1.6.11        well_known

$ sed -n '12,25p' /opt/www/roundcubemail/config/config.inc.php
$config['imap_host'] = 'tls://127.0.0.1:143';
...
// SMTP
$config['smtp_host'] = 'tls://127.0.0.1:587';
$config['smtp_user'] = '%u';
$config['smtp_pass'] = '%p';
$config['smtp_auth_type'] = 'LOGIN';

$ grep -n "plugins" /opt/www/roundcubemail/config/config.inc.php
70:$config['plugins'] = array('managesieve', 'password', 'zipdownload');

$ grep -vnE "^\s*#|^\s*$" /opt/www/iredadmin/settings.py | head -20
5:from libs.default_settings import *
10:webmaster = "postmaster@example.com"
13:default_language = 'en_US'
16:backend = 'mysql'
20:storage_base_directory = "/var/vmail/vmail1"
32:default_mta_transport = "dovecot"
38:min_passwd_length = 8
39:max_passwd_length = 0
44:iredadmin_db_host = "127.0.0.1"
45:iredadmin_db_port = "3306"
46:iredadmin_db_name = "iredadmin"
47:iredadmin_db_user = "iredadmin"
48:iredadmin_db_password = "<安装时随机生成>"
53:vmail_db_host = "127.0.0.1"
54:vmail_db_port = "3306"
55:vmail_db_name = "vmail"
56:vmail_db_user = "vmailadmin"
57:vmail_db_password = "<安装时随机生成>"
69:amavisd_enable_logging = True
71:amavisd_db_host = "127.0.0.1"

$ grep -E '^plugins = ' -A 1 /opt/iredapd/settings.py
plugins = ["reject_null_sender", "wblist_rdns", "reject_sender_login_mismatch", "greylisting", "throttle", "amavisd_wblist", "sql_alias_access_policy", "sql_ml_access_policy"]

$ grep -nE '10024|10026|policy_bank|dkim_key|dkim_signing|dkim_verification' /etc/amavis/conf.d/50-user | head -10
45:$inet_socket_port = [10024, 10026, 10027, 9998];
47:$policy_bank{'MYNETS'} = {   # mail originating from @mynetworks
55:$interface_policy{'10026'} = 'ORIGINATING';
56:$policy_bank{'ORIGINATING'} = {
83:$policy_bank{'MLMMJ'} = {
86:    enable_dkim_signing => 1,   # enable DKIM signing for outbound
498:$enable_dkim_verification = 1;
501:dkim_key('example.com', 'dkim', '/var/lib/dkim/example.com.pem');

$ grep -E '^\[|^enabled|^maxretry|^bantime' /etc/fail2ban/jail.local | head -14
[DEFAULT]
bantime     = 3600
maxretry    = 5

30   3   *   *   *   /bin/bash /var/vmail/backup/backup_mysql.sh

# iRedAPD: Clean up expired tracking records hourly.
1   *   *   *   *   python3 /opt/iredapd/tools/cleanup_db.py >/dev/null

# iRedAPD: Convert SPF DNS record of specified domain names to IP
#          addresses/networks hourly.
2   *   *   *   *   python3 /opt/iredapd/tools/spf_to_greylist_whitelists.py >/dev/null