
Some ISPs offer YouTube/Netflix/Facebook for free. How do they monitor that? - kuba-orlik
In Poland, it is common for mobile ISPs to offer plans with limited amount of bandwidth per month, with exclusion of some popular apps. So for example all traffic from youtube is not counted towards the data cap, but any other casual everyday browsing is.<p>Aside from net neutrality issues, I am wondering how is this achieved in the HTTPS age? How does the ISP know which packets to count towards the data cap?<p>It doesn&#x27;t seem to be per-app, and no proxy is installed. My guess is that it&#x27;s done by some kind of packet inspection. But what exactly are they looking at?
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forgotmypw
It should be enough to look at the IP address.

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kuba-orlik
Yeah, but all traffic from googlevideo.com is uncapped, but traffic from
google.com is... how do they know which IPs to block? Youtube has like a ton
of them and they probably change from time to time. If it's IP-based, how do
they compile a list of IPs that are guaranteed to be youtube video content,
but not anything else?

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forgotmypw
>Youtube has like a ton of them and they probably change from time to time.

While that's true, it is not that many IPs, and they do not change that much.

Maintaining a list of IPs for YouTube, Netflix, and other mainstream services
is probably a couple hours of work per week at most, probably distributed
between multiple people in whatever department handles it.

