Re: large BCP38 compliance testing

[Barry Greene <bgreene () senki org>]

On Oct 2, 2014, at 6:23 PM, Jérôme Nicolle <jerome () ceriz fr> 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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