Looks like via - indicates that you have been routed via a proxy - however - this is information only - you need to make sure you caching headers are being set correctly so that the proxy takes the correct action.
Currently there is no caching headers being set on your request.
If you do not want it to be cached - then set the following header:
Cache-Control: no-cache
See http://www.w3.org/Protocols/HTTP/Issues/cache-private.html