这个地址本身没有部署 web 。
curl -Iv
connectivitycheck.gstatic.com/generate_204* Trying 203.208.51.95...
* Connected to
connectivitycheck.gstatic.com (203.208.51.95) port 80 (#0)
> HEAD /generate_204 HTTP/1.1
> Host:
connectivitycheck.gstatic.com> User-Agent: curl/7.47.0
> Accept: */*
>
< HTTP/1.1 204 No Content
HTTP/1.1 204 No Content
< Content-Length: 0
Content-Length: 0
< Date: Sun, 12 Mar 2017 03:18:59 GMT
Date: Sun, 12 Mar 2017 03:18:59 GMT