On Oct 2, 2014, at 6:23 PM, Jérôme Nicolle <[email protected]> wrote:
> > > Le 02/10/2014 12:28, Nick Hilliard a écrit : >> It would probably be more productive to pressurise transit providers to >> enforce bcp38 on their customer links. > > This. But let me ask you, how many transit provider actually implement > strict prefix-filtering ? I've seen many using a max-prefix as their > sole defense. > > Now, let's consider what you want is to match an interface ACL to > prefixes received on a BGP session runing through the same interface. > Ain't that what uRPF-strict is all about ? uRPF Strict mode is NOT a tool to use on the transit connections. It was built for the SP-Customer connections. uRPF VRF mode _was_ built for the transit connections. You can take all the prefixes received from the peer and stick them into a VRF. You can then check all the incoming packet source addresses against that list. If there is no match, then it was not in the BGP advertisements.
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