squid正反向代理及平衡轮询

squid正向代理

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原理：一台不能上网的机器通过代理可以访问不能访问的网站
这里我拿我的真机来做代理，虚拟机通过代理访问网站
真机Operating System: Red Hat Enterprise Linux Server 7.2 (Maipo)

squid安装和配置更改

真机（可以上网）IP：172.25.254.56

 [root@dream software]# yum install -y squid                     ###下载squid
 [root@dream software]# vim /etc/squid/squid.conf
  55 # And finally deny all other access to this proxy
  56 http_access allow all                                       ###允许所有人连接
  57 
  58 # Squid normally listens to port 3128
  59 http_port 3128
  60 
  61 # Uncomment and adjust the following to add a disk cache directory.
  62 cache_dir ufs /var/spool/squid 100 16 256                   ###100M，/var/spool/squid中16个一级目录，256个2级目录
  [root@dream squid]# systemctl start squid
  [root@dream 00]# systemctl stop firewalld

如果防火墙未关:开启3128端口访问权限

在虚拟机中的浏览器：

IP:172.25.254.125

测试

浏览器的主机ping www.baidu.com 网络不通，但是浏览器能够上网

squid反向代理

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这里我用2台虚拟机，一台IP：172.25.254.125 一台IP：172.25.254.225

IP:172.25.254.125

注意：这台虚拟机的httpd服务要关闭

 [root@server ~]# yum install -y squid
 [root@server ~]# vim /etc/squid/squid.conf                            ###可以/usr/share/doc/squid-3.3.8/squid.conf.documented查看帮助
  55 # And finally deny all other access to this proxy
  56 http_access allow all
  57 
  58 # Squid normally listens to port 3128
  59 http_port 80 vhost vport                                          ###通过80端口访问，虚拟用户，虚拟端口                               
  60 cache_peer 172.25.254.225 parent 80 0 no-query                    ###通过80访问172.25.254.156，0没有后备，no-query：告诉服务器没有后备
  61
  62 # Uncomment and adjust the following to add a disk cache directory.
  63 cache_dir ufs /var/spool/squid 100 16 256
 [root@server ~]# systemctl start squid
 [root@server ~]# systemctl stop firewalld.service

IP:172.25.254.225

 [root@mysql ~]# vim /var/www/html/index.html
 
172.25.254.156
 [root@mysql ~]# systemctl start httpd 

测试

http://172.25.254.125 ###会访问到172.25.254.225的http的默认发布文件

平衡轮询

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IP:172.25.254.125

 vim /etc/squid/squid.conf
 55 # And finally deny all other access to this proxy
 56 http_access allow all
 57 
 58 # Squid normally listens to port 3128
 59 http_port 80 vhost vport
 60 cache_peer 172.25.254.225 parent 80 0 no-query originserver round-robin name=webserver1     ###originserver:指定name=webserver1，代表所以信息，以round-robin（轮询）方式工作
 61 cache_peer 172.25.254.56 parent 80 0 no-query originserver round-robin name=webserver2
 62 cache_peer_domain webserver1 webserver2 www.dream.com                                      ###www.dream.com做轮询                 
 63 # Uncomment and adjust the following to add a disk cache directory.
 64 cache_dir ufs /var/spool/squid 100 16 256
 systemctl restart squid.service

测试

在访问的浏览器的主机中/etc/hosts加入172.25.254.125 www.dream.com
浏览器输入www.dream.com刷新可发现显示的内容会变化