国内偶尔出现 github 访问不稳定，甚至不能访问的情况，怎么解决呢？
根本办法就是修改 hosts 文件
1. windows
打开文件 C:\Windows\System32\drivers\etc\hosts：
# Copyright (c) 1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost
# 在最后加上下面两行
140.82.114.4 github.com
199.232.69.194 github.global.ssl.fastly.net
刷新 dns
打开 cmd 命令行，执行 ipconfig /flushdns
C:\Windows\System32>ipconfig /flushdns
Windows IP 配置
已成功刷新 DNS 解析缓存。
C:\Windows\System32>ipconfig /flushdns
Windows IP 配置
已成功刷新 DNS 解析缓存。
C:\Windows\System32>ipconfig /flushdns
Windows IP 配置
已成功刷新 DNS 解析缓存。
C:\Windows\System32>
2. mac
打开/etc/hosts文件
追加一下命令
http://github.com 140.82.114.4
http://gist.github.com 107.21.116.220
http://help.github.com 207.97.227.252
http://nodeload.github.com 199.27.76.130
http://raw.github.com 107.22.3.110
http://status.github.com 204.232.175.78
http://training.github.com 207.97.227.243