These attributes are being sent by default, there's nothing to configure. Please see https://documentation.meraki.com/zGeneral_Administration/Cross-Platform_Content/Configuring_RADIUS_Authentication_with_a_Sign-on_Splash_Page "Supported RADIUS Attributes When a sign-on Splash Page is configured with RADIUS server, authentication is performed using PAP. The following attributes are present in the Access-Request messages sent from Dashboard to the RADIUS server. Note: Please refer to RFC 2865 for details on these attributes, additional notes for certain attributes are included below. User-Name User-Password Called-Station-ID: Contains (1) the MAC address of the Meraki access point (all caps, octets separated by hyphens) and (2) the SSID on which the wireless device is connecting. These 2 fields are separated by a colon. Example: "AA-BB-CC-DD-EE-FF:SSID_NAME". Calling-Station-ID: Contains the MAC address of the wireless device (all caps, octets separated by hyphens). Example: "AA-BB-CC-DD-EE-FF". Acct-Session-ID Framed-IP-Address NAS-Identifier NAS-IP-Address NAS-Port-Id NAS-Port-Type Service-Type"
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