一、基于电子邮件发送:

电子邮件发送
(1)服务器使用SMTP协议将电子邮件提交至TCP端口25,或由本地客户端通过/usr/bin/sendmail程序进行提交。如果该MTA是最终目标位置,邮件将传递至MDA。否则,将使用MX记录在DNS中查找下一个MTA,并使用SMTP进行转发。
(2)MDA:“邮件发送代理”。MDA将邮件发送至收件人的本地邮件存储位置(默认情况下是/var/spool/mail/user)。Postfix提供自己的MDA,以发送至基于文件的本地默认邮件存储位置/usr/libexec/postfix/local.
(3)转发:电子邮件服务器(MTA)将提交的邮件转发至另一个服务器,以进行发送
(4)排队:失败的发送或转发尝试排队等待,并由MTA定义重试。(默认情况下,Postfix每小时执行此操作一次
(5)拒绝:在首次提交期间,电子邮件被电子邮件服务器拒绝
(6)退回:远程服务器接受电子邮件以进行发送以后,又将该电子邮件退回给始发电子邮件服务器和/或用户
(7)电子邮件以进行发送以后,又将该电子邮件退回给始发电子邮件服务器和/或用户

浅谈SMTP配置(邮件系统)_第1张图片

Postfix由postfix RPM包提供,并通过postfix服务脚本控制。它是一个由多个协同操作程序构成的模块
化程序,它的组件由master进程控制。
Postfix的主配置文件是/etc/postfix/main.cf,可以使用文本编辑器或postconf命令进行编辑。postconf
命令还可用于确定Postfix的所有当前和默认配置设置或逐项确定这些设置。
默认情况下,Postfix仅侦听来自本地主机的传入电子邮件。若要重新配置postfix以接收从远程主机发
送的本地邮件,必须在/etc/postfix/main.cf中设置inet_interfaces = all
对电子邮件进行故障排除时,将在/var/log/maillog中保留所有与邮件相关的操作日志,其中包括关于
被事件和成功事件的信息。mailq命令(或postqueue -p)显示已排队的所有传出邮件的列表。若要尝试
再次立即发送所有已排队的邮件,可以运行postfix flush命令(或postqueue -f);否则,postfix将大
约每小时尝试重新发送一次,直至邮件被接受或过期。


实验环境:
               服务器端server: willis.com   172.25.254.1
               客户端desktop:  desktop.com   172.25.254.2
实验内容: 1.邮件远程发送
                2.邮件别名
                3.邮件群发
                4.空壳邮件服务搭建
                5.不同服务器之间邮件传送(DNS邮件解析)
                6.出栈地址伪装

                 7.客户端主机名/地址限制 :(通过IP限制发件)  
                8.通过发件人地址进行限制 :(通过地址限制发件)
                9.通过收件人地址进行过滤 :(限制收件)         
                   
1.邮件远程发送  1.1服务端           
    1.1-1   systemctl stop firewalld
          yum install postfix   
    1.1-2vim /etc/postfix/main.cf        
         mydomain = willis.com          #收件方看到的方邮件方主机名        
         myorigin = $mydomain        
         inet_interfaces = all          #开启接口      
         #inet_interfaces = localhost   #关闭只允许本地访问        
         mydestination = $myhostname, $mydomain, localhost  #  
     1.1-3.systemctl restart  postfix       
          netstat antlpe |grep master  #查看端口
[root@willis ~]# netstat -antple |grep master
tcp        0      0 0.0.0.0:25              0.0.0.0:*               LISTEN      0          43632      2497/master        
tcp6       0      0 :::25                   :::*                    LISTEN      0          43633      2497/master        
 
  1.2.远程发送端(客户端)
[root@desktop ~]# yum install telnet -y
[root@desktop ~]# telnet 172.25.254.1 25 Trying 172.25.254.1... Connected to 172.25.254.1. Escape character is '^]'. 220 linux.com ESMTP Postfixehlo hello250-linux.com 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN
2.邮件别名      
     2.1.vim /etc/aliases      
         最后添加  admin:    root    ###给root一个别名为admin    
    2.2.postalias /etc/aliases     ###重读别名文件    
    2.3.systemctl restart  postfix    
    2.4.id admin       ###可查看到admin用户不存在      
           mail admin     ###相当于给root用户发送邮件      
           mail        ###查看root用户的邮件
[root@willis ~]# vim /etc/aliases
[root@willis ~]# postalias  /etc/aliases
[root@willis ~]# systemctl restart postfix.service
[root@willis ~]# id willis
id: willis: no such user
[root@willis ~]# mail willis
Subject: hello
hello , my name is willis,how are you.
.
EOT
[root@willis ~]# mail
Heirloom Mail version 12.5 7/5/10.  Type ? for help.
"/var/spool/mail/root": 1 message 1 new
>N  1 root                  Fri Sep  9 10:36  18/567   "hello"
& 1
Message  1:
From [email protected]  Fri Sep  9 10:36:54 2016
Return-Path:
X-Original-To: willis
Delivered-To: [email protected]
Date: Fri, 09 Sep 2016 10:36:54 +0800
To: [email protected]
Subject: hello
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=us-ascii
From: [email protected] (root)
Status: R
hello , my name is willis,how are you.
& q
Held 1 message in /var/spool/mail/root

3.邮件群发  
  1.vim /etc/postfix/moreuser      
      root      
      student    
  2.vim /etc/aliases      
      最后添加 more:  :include:/etc/postfix/moreuser    
  3.postalias /etc/aliases  
   4.systemctl restart  postfix    
   5.mail more       ###群发邮件      
      mail         ###查看root用户的邮件      
      mail -u student ###查看student用户的邮件  
[root@willis ~]# >/var/spool/mail/root
[root@willis ~]# useradd student
[root@willis ~]# vim /etc/postfix/moreuser
                             root
                             student
[root@willis ~]# vim /etc/aliases
[root@willis ~]# postalias /etc/aliases
[root@willis ~]# systemctl restart postfix.service
[root@willis ~]# mail more
Subject: hello-world
hello world.
.
EOT
[root@willis ~]# mail
Heirloom Mail version 12.5 7/5/10.  Type ? for help.
"/var/spool/mail/root": 1 message 1 new
>N  1 root                  Fri Sep  9 10:42  21/661   "hello-world"
& q
Held 1 message in /var/spool/mail/root
[root@willis ~]# mail -u student
Heirloom Mail version 12.5 7/5/10.  Type ? for help.
"/var/mail/student": 1 message 1 new
>N  1 root                  Fri Sep  9 10:42  21/664   "hello-world"
& q
Held 1 message in /var/mail/student
      4.空壳邮件服务搭建    
   4.1.在desktop(另外一台仅中转邮件的服务器,空壳端)上  
       postconf -e "inet_interfaces = all"  
       postconf -e "mydomain = willis.com"  
       postconf -e 'myorigin = $mydomain'  
       postconf -e "mydestination = "  
       postconf -e "relayhost = 172.25.254.1"  
       postconf -e "local_transport = error:local delivery disabled "  
       systemctl restart postfix.service (附注:火墙要关闭systemctl stop firewalld  selinux要置0 setenforce 0 )
[root@desktop ~]# postconf -e "mydomain = willis.com"
[root@desktop ~]# postconf -e 'myorigin = $mydomain'
[root@desktop ~]# postconf -e "mydestination = "
[root@desktop ~]#  postconf -e "relayhost = 172.25.254.1"
[root@desktop ~]# postconf -e "local_transport = error:local delivery disabled "
[root@desktop ~]# systemctl restart postfix.service
   4.2.在主服务器server上  
       postconf -e "mynetworks = 127.0.0.0/8 172.25.254.0/24"
       #接受来自那个网段的邮件  
       systemctl restart postfix.service (附注:火墙要关闭systemctl stop firewalld        selinux要置0 setenforce 0 )
[root@willis ~]# postconf -e "mynetworks = 127.0.0.0/8 172.25.254.0/24"
You have mail in /var/spool/mail/root
[root@willis ~]# systemctl restart postfix.service

    4.3.实验验证    在desktop(另外一台仅中转邮件的服务器)上(> /var/log/maillog       ###清空邮件日志)   mail root    ###发送文件[root@desktop ~]# >/var/log/maillog
[root@desktop ~]# mail root
Subject: beautiful world
Threr are many beautiful things.
.
EOT
[root@desktop ~]# mail
No mail for root

   在主服务器server上( > /var/spool/mail/root ###清空邮件)   mail         ###查看文件 [root@willis ~]# >/var/spool/mail/root
[root@willis ~]# mail
Heirloom Mail version 12.5 7/5/10.  Type ? for help.
"/var/spool/mail/root": 1 message 1 new
>N  1 root                  Fri Sep  9 10:54  21/756   "beautiful world"
& q
Held 1 message in /var/spool/mail/root


5.不同服务器之间的邮件传送(DNS邮件解析记录)    将前面做实验的环境恢复到初始状态。
   vim /etc/postfix/main.cf        
         mydomain = willis.com                
         myorigin = $mydomain        
         inet_interfaces = all                
         #inet_interfaces = localhost          
         mydestination = $myhostname, $mydomain, localhost  
   5-1server端配置dns
hostnamectl set-hostname mail.willis.com
安装DNS:yum install bind -y
1)vim /etc/resolv.conf    
       search willis.com
       nameserver 172.25.254.12)vim /etc/named.rfc1912.zoneszone "willis.com" IN {
       type master;
       file "willis.com.zone";
       allow-update { none; };
};

zone "redhat.com" IN {
       type master;
       file "redhat.com.zone";
       allow-update { none; };
};
3)cd /var/named/  
   cp -p named.localhost willis.com.zone4)vim willis.com.zone$TTL 1D
@       IN SOA  dns.willis.com. root. (
                                       0       ; serial
                                       1D      ; refresh
                                       1H      ; retry
                                       1W      ; expire
                                       3H )    ; minimum
       NS      dns.willis.com.
dns     A       172.25.254.1
willis.com.  MX 1    172.25.254.1.
5)cp -p willis.com.zone redhat.com.zone  
   vim redhat.com.zone$TTL 1D
@       IN SOA  dns.redhat.com. root. (
                                       0       ; serial
                                       1D      ; refresh
                                       1H      ; retry
                                       1W      ; expire
                                       3H )    ; minimum
       NS      dns.redhat.com.
dns     A       172.25.254.1
redhat  MX 1    172.25.254.2.                            
6)systemctl start named    5-2 . desktop端配置
   hostnamectl set-hostname mail.redhat.com  
   1)vim /etc/resolv.conf    
        search   redhat.com      
        nameserver  172.25.254.1
    2)测试      
    mail [email protected]    
    mail [email protected] [root@mail ~]# mail [email protected]
Subject: hello-willis
hello . you are a good boy.
.
EOT
[root@mail ~]# mail [email protected]
Subject: hello goog boy
Are you ok now?
.
EOT
You have new mail in /var/spool/mail/root
[root@mail ~]# mail
[root@mail ~]# mail [email protected]
Subject: hello good boy.
Are you OK now?
.
EOT
[root@mail ~]# mail
Heirloom Mail version 12.5 7/5/10.  Type ? for help.
"/var/spool/mail/root": 1 message 1 new
>N  1 root                  Fri Sep  9 12:24  18/569   "hello good boy."
& 1
Message  1:
From [email protected]  Fri Sep  9 12:24:07 2016
Return-Path:
X-Original-To: [email protected]
Delivered-To: [email protected]
Date: Fri, 09 Sep 2016 12:24:07 +0800
To: [email protected]
Subject: hello good boy.
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=us-ascii
From: [email protected] (root)
Status: R

Are you OK now?

    
  6.出栈地址伪装    6.1服务器端(伪装端)
   vim /etc/postfix/generic    增加    [email protected]     [email protected]    postmap generic        ###生成generic.db文件    postconf -d | grep generic    postconf -e "smtp_generic_maps = hash:/etc/postfix/generic"    systemctl restart postfix.service
   测试        mail [email protected]

[root@willis postfix]# mail [email protected]
Subject: hello.
你好呀
.
EOT

   6.2 接受端
[root@mail ~]# mail
Heirloom Mail version 12.5 7/5/10.  Type ? for help.
"/var/spool/mail/root": 1 message 1 new
>N  1 root                  Fri Sep  9 12:47  21/733   "hello."
& 1
Message  1:
From [email protected]  Fri Sep  9 12:47:10 2016
Return-Path:
X-Original-To: [email protected]
Delivered-To: [email protected]
Date: Fri, 09 Sep 2016 12:47:11 +0800
To: [email protected]
Subject: hello.
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=utf-8
From: [email protected] (root)
Status: R

你好呀

7.客户端主机名/地址限制 :(通过IP限制发件)  
   postconf -e "smtpd_client_restrictions
                                   = check_client_access hash:/etc/postfix/access"  
   vim /etc/postfox/main.cf    
smtpd_client_restrictions = check_client_access hash:/etc/postfix/access,
    vim /etc/postfox/access      
        192.168.0.4   REJECT    
         192.168.0     REJECT
  postmap access  
  systemctl restart postfix 8.通过发件人地址进行限制 :(通过地址限制发件)  
  postconf -e "smtpd_sender_restrictions
                                  = check_sender_access hash:/etc/postfix/sender"  
  vim /etc/postfox/main.cf      
  smtpd_sender_restrictions =
                                       check_sender_access hash:/etc/postfix/sender
    vim /etc/postfix/sender        
             [email protected] REJECT(OK、RELAY)
   postmap sender
   systemctl restart postfix9.通过收件人地址进行过滤 :(限制收件)
        postconf -e "smtpd_recipient_restrictions = check_recipient_access                                    hash:/etc/postfix/recipient"  
        vim /etc/postfox/main.cf                        smtpd_recipient_restrictions = check_recipient_access                                    hash:/etc/postfix/recipient  
        vim /etc/postfix/recipient                            [email protected]  REJECT(OK、RELAY,DISCARDED)
        postmap recipient