curl -v http://192.168.16.228:4000/v2/
*   Trying 192.168.16.228...
* Connected to 192.168.16.228 (192.168.16.228) port 4000 (#0)
> GET /v2/ HTTP/1.1
> Host: 192.168.16.228:4000
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Length: 2
< Content-Type: application/json; charset=utf-8
< Docker-Distribution-Api-Version: registry/2.0
< X-Content-Type-Options: nosniff
< Date: Tue, 02 Feb 2016 12:42:57 GMT
<
* Connection #0 to host 192.168.16.228 left intact