[root@Master ~]# vim /etc/squid/squid.conf   //添加
acl localdomain src 192.168.30.0/24
http_access allow localdomain
这里修改配置文件的第二种方式是
搜索http_access deny all将deny修改为allow，同时注释掉上面添加的两行内容

[root@Master ~]# vim /etc/squid/squid.conf
http_port 3128 transparent   #直接搜索http_port 3128然后在行尾加上一个单词即可

[root@Master ~]# vim /etc/sysctl.conf 

net.ipv4.ip_forward = 1

[root@Master ~]# sysctl -p
net.ipv4.ip_forward = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
[root@Master ~]# service iptables start 
iptables: Applying firewall rules:                         [  OK  ]
[root@Master ~]# iptables -t nat -A POSTROUTING -s 192.168.17.0/24 -j SNAT --to 1922.168.30.130  //SNAT代理内部上网，将内部的地址全部转化为可以上网的地址 192.168.1.63
[root@Master ~]# iptables -t nat -A PREROUTING -s 192.168.17.0/24 -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 3128 //端口转化，来自192.168.2.0，从eth1且端口为80的数据进行数据重定向到3128，代理服务器为你工作
[root@Master ~]# iptables -L -t nat
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination         
REDIRECT   tcp  --  192.168.17.0/24      anywhere            tcp dpt:http redir ports 3128 

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination         
SNAT       all  --  192.168.17.0/24      anywhere            to:192.168.30.130 

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination 

[root@master ~]# vim /etc/squid/squid.conf

http_access  allow all

http_port 3128 vhost #启用虚拟主机
cache_peer 192.168.17.131 parent 80 0 no-query originserver weight=1 name=a 
cache_peer 192.168.17.131 parent 81 0 no-query originserver weight=1 name=b
#no-query和originserver指明了服务器，不查询直接到源服务器
#name对前面的定义做了一个别名
cache_peer_domain a www.servera.com #访问www.servera.com将直接访问到上面定义的17.131的80端口
cache_peer_domain b www.serverb.com
cache_peer_access a allow all
cache_peer_access b allow all

[root@master ~]# service squid restart 
Stopping squid: ................                           [  OK  ]
Starting squid: .                                          [  OK  ]

[root@slave ~]# mkdir /var/www/html/sishen
[root@slave ~]# echo "<h1>This is serverb</h1>" > /var/www/html/index.html
[root@slave ~]# echo "<h1>This is servera</h1>" > /var/www/html/sishen/index.html
[root@slave ~]# vim /etc/httpd/conf/httpd.conf 
.......
Listen 80
Listen 81
............
<VirtualHost *:80>
    ServerAdmin webmaster@dummy-host.servera.com
    DocumentRoot /var/www/html/sishen
    ServerName www.servera.com
    ErrorLog logs/dummy-host.servera.com-error_log
    CustomLog logs/dummy-host.servera.com-access_log common
</VirtualHost>
<VirtualHost *:81>
    ServerAdmin webmaster@dummy-host.serverb.com
    DocumentRoot /var/www/html
    ServerName www.serverb.com
    ErrorLog logs/dummy-host.serverb.com-error_log
    CustomLog logs/dummy-host.serverb.com-access_log common
</VirtualHost>
修改完成后，重启httpd服务

[root@slave ~]# service httpd restart
Stopping httpd: [ OK ]
Starting httpd: [ OK ]

末尾添加如下内容：
192.168.30.130 www.servera.com
192.168.30.130 www.serverb.com