This document explains how to configure an External Splash Page to work on top of your Classic Hotspot infrastructure.
How to configure an SSID with an external splash page with RADIUS
After creating the SSID, access to "Wireless Security" tab and follow the steps described below.

STEP 1
Write your splash page URL in the "Splash Page" field (specify http:// or https://)
STEP 2
Set the client session timeout and the client idle timeout
STEP 3
Configure the walled garden.
For reference How to configure the Walled Garden if you are using an external splash page
STEP4
Select the page to which the user is redirected to after authentication: a landing page or a client defined URL
STEP 5
Configure the RADIUS settings.
For reference How to configure RADIUS settings
STEP 6
Click on APPLY