All these explanations can only go so far as to show that ConEd and its upstreams may have had these prefixes as something that is allowed (due to previous transit relationships) to be annnounced. However presumably all these were transit arrangements with ConEd and ip blocks would have originated from different ASN where a during the accident ConEd actually directly announced prefix as originating from its own ASN. One thing I can think of is that ConEd started doing syncrhonization so all eBGP routes were redistributed into ospf or some other igp protocol. This could led to situation that some previously configured router that redistributes summarized rotues from igp go bgp could think the route needs to be advertised as coming from ConEd and announced it Verio. But I think result of all this should have been that route would be flapping (i.e. they start announcing and then it gets removed from what they learn from upstream and so no longer redistributed to igp and no longer announced; back to the beginning) and they weren't. -- William Leibzon Elan Networks william@elan.net