How, inside the local network, to find out who (what computer) uses the Internet for their needs?

Question

Web traffic analysis

One small company (about 10 machines) uses a home router with a 4G/3G modem. After paying the internet bills, the bosses were wondering if anyone in the company was using the internet for gaming/watching or downloading movies. Actually, the question is how to calculate such an employee (employees) using some program or some other means?
Rhinestone I will say, connections both by air and by cable. There are no servers. Router TP-Link model I will not say for sure. MTS modem.

Answer 1

you will have to wedge a proxy server between the router and clients
Internet-router-proxy-clients
on the proxy server (for example, under freebsd / linux OS) raise squid + sarg for statistics. firewall rules wrap all web traffic (destination ports 80/443) from clients to squid's port 3128.
The bottom line is that the squid will write everything to the logs and the twill will process the log and give a report on each computer in the context of time by day. True, you will also have to raise the web server to view statistics.
In a word, if you can’t do it yourself, it’s better to pay for the work of a specialist