Re: [c-nsp] Peering + Transit Circuits

[William Herrin <bill () herrin us>]

On Tue, Aug 18, 2015 at 4:43 PM, Nick Hilliard <nick () foobar org> wrote:
> On 18/08/2015 20:22, Tim Durack wrote:
> > This has always been my understanding - thanks for confirming. I'm weighing
> > cost-benefit, and looking to see if there are any other smart ideas. As
> > usual, it looks like simplest is best.
>
> i'd advise being careful with this approach: urpf at ixps is a nightmare.

Hi Nick,

This technique described isn't URPF, it's simple destination routing.
The routes I offer you via BGP are the only routes in my table, hence
the only routes I'm capable of routing. If you send me a packet for a
_destination_ I didn't offer to you, I can't route it.

URPF is the opposite of that. I'll only accept packets from you with a
_source_ address which is included in the routes you sent to me.

Regards,
Bill Herrin



-- 
William Herrin ................ herrin () dirtside com  bill () herrin us
Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>