Sorry for littering NANOG with this email, but I'm hoping for a little education on this matter from some of the larger National Service Providers. This morning we had a customer call in concerning a network hole. Upon investigation, I found the following.. BGP routing table entry for 166.82.0.0/16, version 541808 Paths: (1 available, best #1, advertised over IBGP, EBGP) 1793 1239 1790 3505 3505 144.228.159.17 from 144.228.159.17 (144.228.159.1) Origin IGP, metric 0, valid, external, best Community: 1 Dampinfo: penalty 656, flapped 18 times in 02:19:29 Two immediate things came to mind here. 1. This is a /16 that is flapping. 2. The end user is using AS path prepending for some reason. With these two facts in mind, the following questions arise. Anchoring or tying down of a route with a static route to null seems to be a very basic idea (far more basic that AS path prepending), so why isn't this route tied down? I only see one route to this prefix, why are they prepending? (I admit that only the user of this prefix can answer this question, and I also admit that with 53 flaps on the books so far, the other provider may be dampening the route for us *thank you*) Finally, does Sprint not apply *any* dampening to customer routes? My cat is long dead (10 years at least), so it's safe from my curiosity. Chris A. Icide Nap.Net, L.L.C.