nanog mailing list archives

Re: Why not to use RPKI (Was Re: Argus: a hijacking alarm system)


From: John Kemp <kemp () network-services uoregon edu>
Date: Mon, 23 Jan 2012 11:07:50 -0800

On 1/23/2012 7:28 AM, Christopher Morrow wrote:
On Mon, Jan 23, 2012 at 10:19 AM, Yang Xiang
<xiangy08 () csnet1 cs tsinghua edu cn> wrote:
Hi chris,

2012/1/23 Christopher Morrow <morrowc.lists () gmail com>
On Fri, Jan 20, 2012 at 8:08 AM, Yang Xiang
<xiangy08 () csnet1 cs tsinghua edu cn> wrote:
2012/1/20 Arturo Servin <aservin () lacnic net>
while Argus can discover potential hijackings caused by anomalous AS
path.
reading the preceding section (III.B) you check 3 things in the AMM
(anomaly monitoring module)
 1) proper origin (based on what?)
 2) anomalous neighbour (based on what?)
 3) policy anomaly (where did you determine the policy?)

later text seems to imply you track some history (1 months worth) and
use that as a baseline, for at least the neighbour and origin data.
The policy data isn't clearly outlined though, where did that come
from? (there's a note about use of whois, which could cover some of
this, but certainly not all)
yes, we use history as a baseline for both the origin, neighbor and policy
data.
origin data: a history of <prefix, origin_AS> mappings,
neighbor data: a history of every "adjacent two ASes" in all AS paths
received from BGPmon,
policy data: a history of every "adjacent three ASes" (AS triple) in all AS
paths.

origin and neighbor data is intuitive.
for policy data, we do not gather the exact routing policies,
since they are usually private.
In Argus, we use all "adjacent three ASes" in all AS paths as the policy
data.
this is because:
1), AS triples reflect the import/export routing policies;
2), while monitoring BGP updates, we only need to discover 'possible’
hijackings, but not 'exact' hijackings.
  after figure out a possible hijacking, the hijacking identification
process will be launched and make the final judgement.
ok, that seems squirrelly still :(


The data plane testing you propose is from the public route-servers
(eyes), which don't import the path you want, well routeviews I think
doesn't import routes to it's FIB (or maybe I'm mistaken...) but point
being with more than one peer on the routeserver it's not clear you
would be taking the path you actually want to test anyway, is it?
yes, each route-server usually has several route to the target prefix.
In Argus, we use the commands (i.e., "show route exact active-path”) to get
the 'best routes' of the prefix,
and consider it as the route in FIB:
so, take routeviews for example, they peer almost exclusively
ebgp-multi-hop, so any 'best path' you see there isn't actually usable
by the route-server... all traffic has to take the local transport out
of the routeviews system, off to the internet and beyond. So, your
blackhole testing isn't actually testing what you want, I think :(

-chris


Minor correction there.  If you are talking about our IX collectors
(LINX, PAIX,
EQIX Ashburn, SYDNEY, etc.) those are at exchanges and peering
directly.  The
collectors at Univ of Oregon (rv,rv2,rv3,rv4, rv6), yeah, those are
multi-hop.
Doesn't detract from your point, but I think it helps if people are
aware of whether
they are on the exchange or on a multihop when using routeviews collectors.

Only other thing to add, I don't think anyone mentioned Cyclops in this
thread.
Just as another data point, see also: http://cyclops.6watch.net or
http://cyclops.cs.ucla.edu

John Kemp (kemp () routeviews org)




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