I am just starting out in VPN’s and I see that by using it we can bypass geographical restrictions, hide what we browse from ISP etc. If we can mask our usage from ISP, then how can they monitor our data usage? Like if I download a file while on VPN, how do they know that I’m the one downloading it?
It’s like waterline, you can run cocacola, pepsi, rum, whskey, water … well whatever you want. They measure it similarly using volume you have transferred through that pipe with a measuring counter. They dont have to see what it is.
Because physically all traffic goes via your ISPs lines. So your ISP knows your line (copper, phone, optical, …) is connected to and can put a counter on the line. VPN only creates a virtual tunnel and cannot bypass your ISP. I hoe I made it a bit clearer for you.
NetFlow
NetFlow is a feature that was introduced on Cisco routers that provides the ability to collect IP network traffic as it enters or exits an interface. By analyzing the data provided by NetFlow, a network administrator can determine things such as the source and destination of traffic, class of service, and the causes of congestion. A typical flow monitoring setup (using NetFlow) consists of three main components:
Flow exporter: aggregates packets into flows and exports flow records towards one or more flow collectors.
Flow collector: responsible for reception, storage and pre-processing of flow data received from a flow exporter.
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