How to Use the HTTP Redirection & Whitelist
An operator's network can be setup to redirect unknown or disconnected customers to a splash page of their choosing and then allow access only to the servers that the operator has chosen. Ideally, the splash page should show the customer possible reasons why they were disconnected as well as give them options on how to resolve the issue.
Sample Splash: http://s4cst1.azotel.com/redirect/locom/
HTTP redirection and whitelists are setup on a per WIB basis. In order to set them, the operator will have to go to the network tab, click on the Gateways details page, and finally select the WIB they wish to configure.
Next, scroll down to the section labelled Handling of unknown clients. In this section, enter the URL for the HTTP Redirection and the list of, space separated, server IP addresses which can be accessed by unknown/disconnected customers.
The operator will then save the changes and update WIB files under the tools tab.
When a customer is disconnected by the Subscriber Auto Notification and Disconnect (SAND) system, or for any other reason, the customer is blocked from accessing all sites apart from the sites listed in the "whitelist". Typically, an operator enters their mail servers and End User Portal (EUP) in the whitelist. This is done so that their customers can get to their email (mainly the one letting them know that they have been disconnected!), and also get to the EUP in order to make a payment (payment options depend on the operator). The traffic in the "whitelist" uses a separate low priority bucket, so the operator can limit the bandwidth used by unknown/disconnected customers.
Typically in addition to setting up the whitelist, the operator would also setup a "HTTP redirection" URL. This URL acts as a captive portal for any blocked customers, and diverts them to a splash page. This page would typically explain that the customer is cut off, and would include details of how they can make a payment (via a link to the EUP, or via contact details for the operator).