一、首先去C盘找到hosts：C:WindowsSystem32driversetc 就在这个文件夹下
二、复制下面github的映射地址
127.0.0.1 ieonline.microsoft.com
140.82.112.3 github.com
199.232.69.194 github.global.ssl.fastly.net
185.199.108.153 assets-cdn.github.com
185.199.110.153 assets-cdn.github.com
185.199.111.153 assets-cdn.github.com
192.30.253.118 http://gist.github.com
151.101.185.194 http://github.global.ssl.fastly.net
151.101.129.194 http://github.global.ssl.fastly.net
151.101.65.194 http://github.global.ssl.fastly.net
151.101.1.194 http://github.global.ssl.fastly.net
151.101.193.194 http://github.global.ssl.fastly.net
151.101.77.194 http://github.global.ssl.fastly.net
151.101.229.194 http://github.global.ssl.fastly.net
151.101.113.194 http://github.global.ssl.fastly.net
151.101.196.133 http://assets-cdn.github.com
151.101.24.133 http://assets-cdn.github.com
185.199.111.153 http://assets-cdn.github.com
185.199.110.153 http://assets-cdn.github.com
185.199.108.153 http://assets-cdn.github.com
185.199.109.153 http://assets-cdn.github.com
151.101.112.133 http://assets-cdn.github.com
三、去windows系统里面测试：
1、输入ping github.com命令。
2、如果出现下图：
丢失为0就成功了。
3、如果不行，再试一下刷新dns命令：
4、上述都不行，那就没辙了。
