Re: [Sidrops] I-D Action: draft-ietf-sidrops-route-server-rpki-light-02.txt

[Job Snijders <[e-mail]>]

Hi,

On Tue, Jul 25, 2017 at 04:38:38PM +0200, Aris Lambrianidis wrote:
> We’re working on an updated draft to elaborate further on the valid
> path hiding concerns you raised, as well as describing a new
> transitive extended BGP community attribute, (instead of reusing the
> one described in RFC8097), based on Job Snijders’ offline comments.

I elaborated that using a non-transitive extended community to cross
EBGP boundaries (in my opinion) is a mis-use of the community transivity
type. I know of a number of BGP implementations which will not send or
accept non-transitive extended communities across EBGP borders.

I am not sure whether a transitive extended community is the way to go
either. A transitive extended community will allow an adversary to
tunnel through networks which don't recognize the semantics of the "BGP
Prefix Origin Validation State Transitive Extended Community" and
possibly negatively impact such networks. This is the trouble with
communities: the granularity available to limit scope and distributino
is very coarse.

I'm not sure there is a good solution here. Any adversy will tag the
malicious announcement as "this is perfectly valid" and hope the 'valid'
community helps mitigate 'rpki light' barriers.

Kind regards,

Job