Correct - the IP addresss is not known at the point the client is being authenticated.   The RADIUS server sends back an ACCESS_ACCEPT message to the AP to say to let the client connect - and that is the end of the authentication process.  There is nothing to send back the clients IP address.     You could potentially enable RADIUS Accounting - and that might send you the extra info you are after. https://documentation.meraki.com/MR/Encryption_and_Authentication/Configuring_RADIUS_Authentication_with_WPA2-Enterprise#RADIUS_Accounting The documentation says only START and STOP messages are sent, which are at the beggining and end of every client session.  The packets would not be very big. ... View more