背景：首次使用postfix测试收邮件，发邮件
环境：CentOS Linux release 7.8.2003 (Core)，基于VMware Workstations Pro 15
标签：Postfix，Dovecot，多实例
1，配置2个固定IP，多实例，1个IP对应1个实例。192.168.101.8 和 192.168.101.9
vim /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE="Ethernet"
PROXY_METHOD="none"
BROWSER_ONLY="no"
BOOTPROTO="static"
DEFROUTE="yes"
IPV4_FAILURE_FATAL="no"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_FAILURE_FATAL="no"
IPV6_ADDR_GEN_MODE="stable-privacy"
NAME="ens33"
UUID="f6d40cce-367a-4349-9351-511a6235b342"
DEVICE="ens33"
ONBOOT="yes"
IPADDR="192.168.101.8"
IPADDR1="192.168.101.9"
GATEWAY="192.168.101.1"
NETMASK="255.255.255.0"
DNS1="8.8.8.8"
2. 安装Postfix，现在大部分的Linux系统都自带Postfix，无需安装，这里直接进行配置
vim /etc/postfix/main.cf
#接受外部邮件需要更改为
inet_interfaces = all
#加上自己的邮箱域名
mydestination = $myhostname, localhost.$mydomain, localhost, bytedance.shop
#邮件存放目录
home_mailbox = Maildir/
multi_instance_wrapper = ${command_directory}/postmulti -p --
multi_instance_enable = yes
multi_instance_name = postfix-rzhang
multi_instance_group = rzhang
multi_instance_directories = /etc/postfix-2
master_service_disable =
authorized_submit_users = root
myhostname = postfix.bytedance.shop
mydomain = bytedance.shop
myorigin = $mydomain
mynetworks = 192.168.101.8/32,127.0.0.0/8
relay_domains = $mydestination
smtp_bind_address = 192.168.101.8
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = /var/spool/postfix/private/auth
smtpd_sasl_security_options = noanonymous
smtpd_recipient_restrictions = permit_mynetworks,permit_sasl_authenticated,reject_unauth_destination
transport_maps = hash:/etc/postfix/transport
配置master.cf
vim /etc/postfix/master.cf
#设置第一个实例的端口，发信端口可以自定义，但是收信端口是25
192.168.101.8:25 inet n - n - - smtpd
#smtp inet n - n - - smtpd
配置第二个Postfix实例
cp main.cf master.cf /etc/postfix-2/
以下为第二个postfix与第1个不同的地方
vim /etc/postfix-2/main.cf
queue_directory = /var/spool/postfix-2
data_directory = /var/lib/postfix-2
multi_instance_wrapper = ${command_directory}/postmulti -p --
multi_instance_enable = yes
multi_instance_name = postfix-2
multi_instance_group = rzhang#multi_instance_directories = /etc/postfix-2
master_service_disable =
authorized_submit_users = root
myhostname = postfix2.bytedance.shop
mydomain = bytedance.shop
myorigin = $mydomain
mynetworks = 192.168.101.9/32,127.0.0.0/8
relay_domains = $mydestination
smtp_bind_address = 192.168.101.9
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = /var/spool/postfix/private/auth
smtpd_sasl_security_options = noanonymous
smtpd_recipient_restrictions = permit_mynetworks,permit_sasl_authenticated,reject_unauth_destination
#transport_maps = hash:/etc/postfix/transport
配置master
vim /etc/postfix-2/master.cf
192.168.101.9:8025 inet n - n - - smtpd
#smtp inet n - n - - smtpd
3. 安装和配置dovecot
vim /etc/dovecot/dovecot.conf
auth_mechanisms = plain login
mbox_write_locks = fcntl
passdb {
driver = pam
}
service auth {
unix_listener /var/spool/postfix/private/auth {
group = postfix
mode = 0660
user = postfix
}
user = root
}
#ssl_cert =
#ssl_key =
userdb {
driver = passwd
}
ssl = required
vim /etc/dovecot/conf.d/10-mail.conf
mail_location = maildir:~/Maildir
4，启动postfix和dovecot，具体报错根据日志检查
tail -100 /var/log/maillog
其中在发邮件的时候遇到过以下报错
loops back to myself
网上资料说的方法有，在postfix的mydestination加上自己的域名，更改hostname。
我的解决方法是使用多一个postfix实例，更改不同的hostname；然后发往自己的域名的时候设置转发，使用第二个postfix来发送。
vim /etc/postfix/transport
bytedance.shop smtp:[192.168.101.9]:8025
然后hash
postmap /etc/postfix/transport
5，更改DNS
vim /etc/hosts
192.168.101.8 bytedance.shop
192.168.101.8 postfix.bytedance.shop
192.168.101.9 postfix2.bytedance.shop
firewall-cmd --permanent --zone=public --add-port=25/tcp
firewall-cmd --permanent --zone=public --add-port=110/tcp
firewall-cmd --permanent --zone=public --add-port=995/tcp
firewall-cmd --reload
firewall-cmd --list-all
6，检查postfix是否启动成功
一般显示如下代表成功
[root@rayhung test]# telnet 192.168.101.8 25
Trying 192.168.101.8...
Connected to 192.168.101.8.
Escape character is '^]'.
220 postfix.bytedance.shop ESMTP Postfix
[root@rayhung test]# telnet 192.168.101.9 8025
Trying 192.168.101.9...
Connected to 192.168.101.9.
Escape character is '^]'.
220 postfix2.bytedance.shop ESMTP Postfix
7，开设邮箱
useradd test
passwd test
[root@rzhang]# cd /home/test/;ll
total 0
激活邮箱
[root@rayhung test]# telnet 192.168.101.8 110
Trying 192.168.101.8...
Connected to 192.168.101.8.
Escape character is '^]'.
+OK Dovecot ready.
user test
+OK
pass yourpassword
+OK Logged in.
quit
+OK Logging out.
Connection closed by foreign host.
检查邮箱
[root@rayhung test]# cd /home/test/Maildir/;ll
total 12
drwx------. 2 test test 6 Sep 20 13:36 cur
-rw-------. 1 test test 400 Sep 20 13:36 dovecot.index.log
-rw-------. 1 test test 51 Sep 20 13:36 dovecot-uidlist
-rw-------. 1 test test 8 Sep 20 13:36 dovecot-uidvalidity
-r--r--r--. 1 test test 0 Sep 20 13:36 dovecot-uidvalidity.5f66ea55
drwx------. 2 test test 6 Sep 20 13:36 new
drwx------. 2 test test 6 Sep 20 13:36 tmp
8，安装foxmail进行收发测试
这里使用110端口遇到问题，所以所以使用995
rcheung@bytedance.shop发邮件给test@bytedance.shop
收到邮件
检查日志也是发送成功
grep "test@bytedance.shop" /var/log/maillog
Sep 20 13:46:39 rayhung postfix-rzhang/smtp[2285]: 879228CD7C: to=