One of my ISP clients is leaving, and the person who was assigning IP's when they became our client chose to give them class C's scattered throughout our block. These are Sprint IP's which are assigned to us with our Sprint circuit. Our former client is getting a Sprint T1 and asking Sprint to route these class C's to them rather than us, and they tell me that Sprint appears willing. They don't have an AS, but they're getting another local ISP to advertise the IP's for them. I normally wouldn't agree to participate in such a mess, but we're shutting off the Sprint circuit in a couple of months, and I can't see making them re-IP hundreds of domains under the circumstances. Has anyone done something like this? I'm wondering how much it will increase the CPU load on my router. I'm already running at 20% average, and if it gets much over that I start dropping ICMP packets. I know enough BGP to stop advertising the appropriate class C's, but I'm not sure that this won't cause problems that I haven't considered. Will anyone refuse to accept advertisements which send adjacent /24's to different places? Is this an officially "broken" setup, or is it just ugly?