20-default.list Website may be down.

错误描述

ERROR: cannot download default sources list from:
https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list
Website may be down.

解决方法：修改DNS

1. Windows打开C:/windows/system32/drivers/etc/hosts，追加下面内容后刷新DNS缓存ipconfig /flushdns
2. Linux打开/etc/hosts，追加下面内容，无需刷新缓存
3. Mac打开/etc/hosts，追加下面内容，使用sudo killall -HUP mDNSResponder刷新DNS缓存

# GitHub Start
52.74.223.119     github.com
192.30.253.119    gist.github.com
54.169.195.247    api.github.com
185.199.111.153   assets-cdn.github.com
151.101.76.133    raw.githubusercontent.com
151.101.76.133    gist.githubusercontent.com
151.101.76.133    cloud.githubusercontent.com
151.101.76.133    camo.githubusercontent.com
151.101.76.133    avatars0.githubusercontent.com
151.101.76.133    avatars1.githubusercontent.com
151.101.76.133    avatars2.githubusercontent.com
151.101.76.133    avatars3.githubusercontent.com
151.101.76.133    avatars4.githubusercontent.com
151.101.76.133    avatars5.githubusercontent.com
151.101.76.133    avatars6.githubusercontent.com
151.101.76.133    avatars7.githubusercontent.com
151.101.76.133    avatars8.githubusercontent.com
# GitHub End

补充：（用来查询域名解析地址的工具）
DNS查询-站长工具: http://tool.chinaz.com/dns/
IP或域名查询-查询网: https://site.ip138.com/

参考文章：https://zhuanlan.zhihu.com/p/107691233

20-default.list Website may be down.

原文：https://www.cnblogs.com/zhyantao/p/12768362.html