[c-nsp] redirecting links to a given web page question

[Scott Granados]

Hi, wondering if anyone has worked out a way to do this.

Say we have a network with all cisco devices, mainly 7200 routers and various switches, nothing exotic.  Customers attach via various methods primarily the standard T1's that are handed off on DS3 loops or metro E, that sort of thing.  
	Is there a clean way to redirect say non paying customers to a payment portal much like a wireless provider pushes you through an authentication portal or 4G provider dumps you to a page notifying you to call customer service?  I'm not even sure what you call this feature so not sure what to google for.  Is anyone out there doing this sort of thing or what should I look for to learn more.  Any pointers would be appreciated.

Thank you
Scott