[External] Re: uPRF strict more

Thu Sep 30 16:21:13 UTC 2021

On Thu, 30 Sept 2021 at 19:00, Hunter Fuller via NANOG <nanog at nanog.org> wrote:

> What it does allow is for *deliberate* blackholing for traffic; if you
> null-route a prefix, you now block incoming traffic from that subnet
> as well. This can be useful and it is how we are using URPF.

I don't think it is implied here, but just for clarification this is
implementation detail. Loose and blackhole route does not imply this
behaviour, It might, it might not, depending on vendor/implementation.
JunOS by default considers null route as loose path satisfied, and you
need 'set forwarding-options rpf-loose-mode-discard family X' to
behave like you explain.

-- 
  ++ytti