What does that even mean? Every ISP has it's own filtering system, some (or maybe even most of them) are custom built ones. There is no such thing as single government approved DPI.
That’s right, but basically dpi sends tcp reset in case of https or 302 redirect in case of http before target server response, since it’s located nearer. There’s a tool to bypass this, so you can read more there. https://github.com/ValdikSS/GoodbyeDPI