Internet traffic for my office is being routed like this:
Devices -> router -> untrusted proxy service -> internet.
I'm being charged for bandwidth used through the proxy. Is there any way to accurately measure bandwidth usage at my modem? How would I know if the proxy is adding hidden data to http responses in order to inflate my monthly usage stats?
For example: I send a get request to example.com/, the normal response body would be "OK", but my proxy changes the response body to " Ok abcdefg<\span>
Any way go detect this?