What is "arubalp" parameter noticed during Captive portal redirection ?
Arubalp parameter that we see during CP redirection is because of the enhancement "Landing Page" that was introduced to improve the Captive portal performance.
Prior to this enhancement , the controller always sent the HTTP 302 in response to a HTTP GET packet to redirect the client to the captive portal page.
We had performance issues with the background apps running in the smart devices when the user is in pre-authenticated role. In order to optimize captive portal we started sending HTTP 200 OK when we get an HTTP GET packet, along with the arubalp parameter.
When the client comes back requesting for the same URL along with the arubalp parameter, we would send the HTTP 302 redirect.The captive portal performance improved significantly as a result of this since only legitimate Browsers will response back for the HTTP ok
The Landing Page feature was introduced from 126.96.36.199 and 188.8.131.52