Le 2018-03-06 19:39, Barry Greene a écrit : >> On Mar 2, 2018, at 1:53 PM, Fabien VINCENT (NaNOG) <list-na...@beufa.net> >> wrote: >> Hope one day the 3rd mode of uRPF will be something else than a plan ... >> uRPF is not very usefull when multi homed. And as far as I know, multi >> homed networks are increasing as fast as PNI development ;) > > This was working microcode code when I left in 2008. Several operators > tested, but none deployed (no pushing or pulling).
Yep, but saw only reference of it, but no real CLI implementation (especially on Cisco), so I guess it's not a killer feature to sell routers ;) In 2005 : https://www.cisco.com/c/dam/en_us/about/security/intelligence/urpf.pdf "A third phase is currently under way that will create a way to have strict enforcement of the uRPF check on individual ISP-ISP edges. Here, external BGP (eBGP) peer sessions will send specific prefixes to a dedicated Virtual routing and forwarding (VRF) table. This will allow uRPF to query the VRF table that contains all the routes for that specific eBGP peering session over the interface, thus verifying (authorizing) the source addresses of packets matching the advertised routes from the peered ISP" That's obviously not so sexy, but I guess the problem is on hardware performance, as the prefer method should to have a look on BGP tables, and uRPF is done on FIB / ASIC level. Sadly, seems not possible right ? -- FABIEN VINCENT _@beufanet_