我正在尝试设置Postfix和Dovecot，后者将虚拟用户存储在 MySQL 数据库中，遵循本指南（但在这里我回顾一下所有内容，因为我在评论后修复的指南中有一些“错误”）。序言：我从 Ubuntu 存储库安装了、Postfix和Dovecot。postfix-mysqldovecot-mysql

让我们从 Postfix 配置开始：

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no   
readme_directory = no

myhostname = localhost
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = 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

relay_domains = *
virtual_alias_maps = proxy:mysql:/etc/postfix/virtual_alias_maps.cf
virtual_mailbox_domains = proxy:mysql:/etc/postfix/virtual_mailbox_domains.cf
virtual_mailbox_maps = proxy:mysql:/etc/postfix/virtual_mailbox_maps.cf
virtual_mailbox_base = /home/vmail
virtual_mailbox_limit = 512000000
virtual_minimum_uid = 5000
virtual_transport = virtual
virtual_uid_maps = static:5000
virtual_gid_maps = static:5000
local_transport = virtual
local_recipient_maps = $virtual_mailbox_maps
transport_maps = hash:/etc/postfix/transport

smtpd_sasl_auth_enable = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = /var/run/dovecot/auth-client
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_relay_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_sasl_security_options = noanonymous
smtpd_sasl_tls_security_options = $smtpd_sasl_security_options
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/ssl/private/server.crt
smtpd_tls_key_file = /etc/ssl/private/server.key
smtpd_sasl_local_domain = $myhostname
broken_sasl_auth_clients = yes
smtpd_tls_loglevel = 1

然后我创建了用户vmail来存储电子邮件：

groupadd -g 5000 vmail
useradd -u 5000 -g vmail -s /usr/bin/nologin -d /home/vmail -m vmail

以及 MySQL 数据库和用户来存储有关域和虚拟用户的信息：

CREATE DATABASE postfix_db;
USE postfix_db;
CREATE USER postfix_user@localhost IDENTIFIED BY 'password';
GRANT ALL ON postfix_db.* TO postfix_user@localhost;
FLUSH PRIVILEGES;

然后我创建了与域、转发和用户相关的表：

CREATE TABLE `domains` (
  `domain` varchar(50) NOT NULL default "",
  PRIMARY KEY  (`domain`),
  UNIQUE KEY `domain` (`domain`)
);


CREATE TABLE `forwardings` (
  `source` varchar(80) NOT NULL default "",
  `destination` text NOT NULL,
  PRIMARY KEY  (`source`)
);

CREATE TABLE `users` (
  `email` varchar(80) NOT NULL default "",
  `password` varchar(20) NOT NULL default "",
  `quota` varchar(20) NOT NULL default '20971520',
  `domain` varchar(255) NOT NULL default "",
  UNIQUE KEY `email` (`email`)
);

我在表中添加了我的域（正确设置了 A 和 MX 记录）：

INSERT INTO `domains` VALUES ('virtualdomain.tld');

以及与该域相关的帐户：

INSERT INTO `users` VALUES ('[email protected]', ENCRYPT('password'), '20971520', 'virtualdomain.tld');

然后我创建了一个自签名证书：

cd /etc/ssl/private/
openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:2048 -out server.key
chmod 400 server.key
openssl req -new -key server.key -out server.csr
openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt
chmod 444 server.crt

然后是我在 Postfix 配置中引用的文件：

/etc/postfix/virtual_alias_maps.cf

user = postfix_user
password = hunter2
hosts = localhost
dbname = postfix_db
table = domains
select_field = domain
where_field = domain

/etc/postfix/virtual_mailbox_domains.cf

user = postfix_user
password = hunter2
hosts = localhost
dbname = postfix_db
table = forwardings
select_field = destination
where_field = source

/etc/postfix/virtual_mailbox_maps.cf

user = postfix_user
password = hunter2
hosts = localhost
dbname = postfix_db
table = users
select_field = concat(domain,'/',email,'/')
where_field = email

接着

touch /etc/postfix/transport
postmap /etc/postfix/transport

现在我删除了默认的 Dovecot 配置文件，将其替换为：

protocols = imap
auth_mechanisms = plain
passdb {
    driver = sql
    args = /etc/dovecot/dovecot-sql.conf
}
userdb {
    driver = sql
    args = /etc/dovecot/dovecot-sql.conf
}

service auth {
    unix_listener auth-client {
        group = postfix
        mode = 0660
        user = postfix
    }
    user = root
}

mail_home = /home/vmail/%d/%u
mail_location = maildir:~

ssl_cert = </etc/ssl/private/server.crt
ssl_key = </etc/ssl/private/server.key

我创建了/etc/dovecot/dovecot-sql.conf文件：

driver = mysql
connect = host=localhost dbname=postfix_db user=postfix_user password=hunter2
# The new name for MD5 is MD5-CRYPT so you might need to change this depending on version
default_pass_scheme = MD5-CRYPT
# Get the mailbox
user_query = SELECT '/home/vmail/%d/%u' as home, 'maildir:/home/vmail/%d/%u' as mail, 5000 AS uid, 5000 AS gid, concat('dirsize:storage=',  quota) AS quota FROM users WHERE email = '%u'
# Get the password
password_query = SELECT email as user, password, '/home/vmail/%d/%u' as userdb_home, 'maildir:/home/vmail/%d/%u' as userdb_mail, 5000 as  userdb_uid, 5000 as userdb_gid FROM users WHERE email = '%u'
# If using client certificates for authentication, comment the above and uncomment the following
#password_query = SELECT null AS password, ‘%u’ AS user

...最后重新启动 dovecot 和后缀：

service postfix dovecot restart

问题是，当我尝试向 发送电子邮件时[email protected]，我在日志中看到：

NOQUEUE: reject: RCPT from blablabla.com[xxx.xxx.xxx.xxx]: 451 4.3.0 <[email protected]>: Temporary lookup failure; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<blablabla.com>

并且邮件因错误而退回

550 5.1.1 "Recipient address rejected: User unknown in virtual alias table"