It works in theory, but to get every ISP and hosting provider to ACL their edges and maintain those ACL's for every customer no matter how large might be a bit difficult. Also, what about non-BGP customers or customers that just accept a default route? Or even customers that just want return traffic to come in a different link for some reason. ISP's would suddenly become giant traffic registries. 2012/2/8 George Bonser <gbonser@seven.com>
From: Keegan Holley
How do you stop it?
A provider knows what destination IP traffic they route TO a customer, don't they? That should be the only source IPs they accept FROM a customer.
If you don't route it TO the customer, you shouldn't accept it FROM the customer unless you have made special arrangements with them and verified they are entitled to source the traffic from the desired IPs.