Because the path was broken everytime the bgp session was established and rewriting the routing table with more specific routes? ----- Original Message ----- From: "Randy Bush" <randy@psg.com> To: "North American Network Operators Group" <nanog@nanog.org> Sent: Thursday, 30 September, 2010 2:37:43 PM Subject: Re: BGP next-hop i was recently bitten by a cousin of this research router getting an ebgp multi-hop full feed from 147.28.0.1 (address is relevant) it is on a lan with a default gateway 42.666.77.11 (address not relevant), so it has ip route 0.0.0.0 0.0.0.0 42.666.77.11 massive flapping results. it seems it gets the bgp route for 147.28.0.0/16 and then can not resolve the next hop. it would not recurse to the default exit. of course it was solved by ip route 147.28.0.0 255.255.0.0 42.666.77.11 but i do not really understand in my heart why i needed to do this. randy