在hosts文件中添加如下内容：
192.30.253.112 github.com
192.30.253.119 gist.github.com
151.101.100.133 assets-cdn.github.com
151.101.100.133 raw.githubusercontent.com
151.101.100.133 gist.githubusercontent.com
151.101.100.133 cloud.githubusercontent.com
151.101.100.133 camo.githubusercontent.com
151.101.100.133 avatars0.githubusercontent.com
151.101.100.133 avatars1.githubusercontent.com
151.101.100.133 avatars2.githubusercontent.com
151.101.100.133 avatars3.githubusercontent.com
151.101.100.133 avatars4.githubusercontent.com
151.101.100.133 avatars5.githubusercontent.com
151.101.100.133 avatars6.githubusercontent.com
151.101.100.133 avatars7.githubusercontent.com
151.101.100.133 avatars8.githubusercontent.com
即可。
关于hosts文件，其作用是包含IP地址和host name(主机名)的映射关系。windows系统下路径为C:\Windows\System32\drivers\etc\hosts，linux系统下为/etc/hosts，没有的话就自己创建一个记事本文件，再把格式后缀删掉，修改时以记事本方式打开即可。