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802.1X consists of blocking all packets at the client's point of access into the network, including all broadcast packets, etc. It is possible on Wi-Fi, ethernet and other mediums.
Architecture
Things to mention:
Re-auth, accounting, request from server, features supported by TP-Link NASes
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Difference between auth systems: PEAP, TTLS, TLS
RADIUS is the protocol, it can be used for many purposes and many authentication methods can be used.
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