题目要求
服务器AppSrv上的工作任务
5. MAIL（POSTFIX-SMTPS & DOVECOT-IMAPS）
Postfix
sdskill.com 的邮件发送服务器
支持smtps(465)协议连接，使用Rserver颁发的证书,证书路径/CA/cacert.pem
创建邮箱账户“user1~user99”（共99个用户），密码为Chinaskill20!；
Dovecot sdskill.com 的邮件接收服务器；
支持imaps（993）协议连接，使用Rserver颁发的证书，证书路径/CA/cacert.pem；
请保留至少两个用户已成功登录并能正常收发邮件，以方便测试.
项目实施
安装：（Centos只允许安装dovecot，因为postfix默认安装好了）
[root@appsrv ~]# yum install dovecot -y
申请证书：（这里我们用的自签名证书，如果需要机构上面那个apache服务以及做过）
[root@appsrv ~]# mkdir /CA
[root@appsrv ~]# openssl genrsa -out /CA/postfix.key
Generating RSA private key, 2048 bit long modulus
.....................................+++
.......................+++
e is 65537 (0x10001)
postfix证书：
[root@appsrv ~]# openssl req -new -x509 -key /CA/postfix.key -out /CA/postfix.crt
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:China
Locality Name (eg, city) [Default City]:ShangDong
Organization Name (eg, company) [Default Company Ltd]:skills
Organizational Unit Name (eg, section) []:Operations Departments
Common Name (eg, your name or your server's hostname) []:smtp.sdskills.com
Email Address []:
[root@appsrv ~]#
dovecot证书：
[root@appsrv ~]# openssl genrsa -out /CA/dovecot.key
Generating RSA private key, 2048 bit long modulus
.......+++
.......................................................................................................+++
e is 65537 (0x10001)
[root@appsrv ~]# openssl req -x509 -new -key /CA/dovecot.key -out /CA/dovecot.crt
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:China
Locality Name (eg, city) [Default City]:ShangDong
Organization Name (eg, company) [Default Company Ltd]:skills
Organizational Unit Name (eg, section) []:imap.sdskills.com
Common Name (eg, your name or your server's hostname) []:
Email Address []:
[root@appsrv ~]#
配置postfix
[root@appsrv ~]# vim /etc/postfix/main.cf
75行：myhostname = mail.sdskills.com //本机主机名,可以为 wjy.com
83行：mydomain = sdskills.com //服务器域名
99行：myorigin = $mydomain //初始域名
112行：inet_interfaces = all //网卡选择
115行： #inet_interfaces = localhost //注释115行
164行：mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain //目标域 or 注释164行，取消注释165行
264行：mynetworks = 0.0.0.0/0 //以下网段可以通过
419行：home_mailbox = Maildir/ //邮件目录，在用户家目录下
670行：smtpd_use_tls = yes
671行：smtpd_tls_cert_file = /CA/postfix.crt
672行：smtpd_tls_key_file = /CA/postfix.key
关闭普通端口开启465端口：
[root@appsrv ~]# vim /etc/postfix/master.cf
11行：#smtp inet n - n - - smtpd ##注释掉25端口
16行：smtps inet n - n - - smtpd ##开启465端口
28行: -o smtpd_tls_wrappermode=yes ##取消注释，启动证书认证
配置dovecot：
[root@appsrv ~]# vim /etc/dovecot/dovecot.conf
24行:protocols = imaps ##启用 imaps
[root@appsrv ~]# vim /etc/dovecot/conf.d/10-auth.conf
10行:disable_plaintext_auth = no
[root@appsrv ~]# vim /etc/dovecot/conf.d/10-mail.conf
24行: mail_location = maildir:~/Maildir ##取消注释
[root@appsrv ~]# vim /etc/dovecot/conf.d/10-ssl.conf
14行:ssl_cert = </CA/dovecot.crt
15行:ssl_key = </CA/dovecot.key
创建99个用户：
[root@appsrv ~]# for i in $(seq 1 99);do useradd user$i;done
[root@appsrv ~]# for i in $(seq 1 99);do echo "Chinaskill20"|passwd --stdin user$i;done
更改用户 user1 的密码 。
passwd：所有的身份验证令牌已经成功更新。
更改用户 user2 的密码 。
passwd：所有的身份验证令牌已经成功更新。
更改用户 user3 的密码 。
passwd：所有的身份验证令牌已经成功更新。
更改用户 user4 的密码 。
passwd：所有的身份验证令牌已经成功更新。
更改用户 user5 的密码 。
passwd：所有的身份验证令牌已经成功更新。
.....................................
[root@appsrv ~]#
重启服务并测试：
[root@appsrv ~]# systemctl restart postfix.service
[root@appsrv ~]# systemctl restart dovecot.service
客户端ping测试：
