Sat, Jul 02, 2016 at 07:44:02PM +0900, Randy Bush:
and you are kinda peotected by the community not being well-known,
i.e. different for each upstream. the attacker has to know the
community for each upstream and be able to not only inject the prefix
but also tag it with the correct community for each upstream.
Your argument comes down to "security through obscurity"
no. non-transitiveness through local naming, the reason this has not
allowed serious damage in current practice.
randy
a receiving operator could limit scope, if they chose. something like
route-map foo p 10
match community blackhole
match as-path ^([0-9]+_){1,2}$
set ip next-hop null0
route-map foo d 20
match community blackhole
route-map foo ...