radius server attribute 4

This command specifies the RADIUS (Remote Authentication Dial In User Service) client to use the NAS-IP Address attribute in the RADIUS requests. If the specific IP address is configured while enabling this attribute, the RADIUS client uses that IP address while sending NAS-IP-Address attribute in RADIUS communication.

Format radius server attribute 4 [ipaddr]
Mode Global Config
4 NAS-IP-Address attribute to be used in RADIUS requests.
ipaddr The IP address of the server.