[j-nsp] Am I carrying this route or not ?

[Payam Chychi]

Carry a route is the same as accepting a route and having it become active, allowing traffic to traverse your network to the destination. In this case the user is asking you to drop the route (attack traffic) at your edge if possible and not to carry it through your network and deliver it to the end destination(his network) because its probably saturating or causing him performance issues. 

Normally networks well have a global community string that they can tag a route with and it will send it to null0, dropping that traffic at the edge v.s the user withdrawing its -/24 route from the advertise table. You can also go on the peering router and set the next hop route for the attacked destination ip to null0 (discard) and only traffic traversing that one router well drop the traffic (global community well handle this if you  have a multi homed network)

Local nullroute example:
"Set routing-options static route x.x.x.x/32 discard" ... Something like this

All your doing is dropping traffic for x.x.x.x/x at your edge, most cases its a /32 nullroute. 

Google is your friend :)
Cheers,
-- 
Payam Chychi
Network Engineer / Security Specialist


On Sunday, 24 March, 2013 at 6:47 AM, Zehef Poto wrote:

> Hey guys,
> 
> Thank you all for the very valuable input. Actually yes, Tobias is right,
> I'm having this question because of the (quoted by Tobias) e-mail we got
> yesterday across several IXPs.
> 
> I just don't understand what is to "carry a route in my backbone". Am I not
> supposed to know all of (or most of) the Internet routes, since I work with
> tier-1 upstream providers ? As a consequence, it means I'm carrying all
> these routes right ?
> 
> A "show route X/22" tells that it was advertised by an eBGP peer on one of
> my edge routers, and the three other ones learnt this same route via OSPF.
> 
> This is where I'm completely confused. What am I supposed to do to "carry"
> a route or not ?
> 
> Thanks again,
> 
> 2013/3/24 Tobias Heister <lists at tobias-heister.de>
> 
> > Hi All,
> > 
> > Am 24.03.2013 00:26, schrieb Jeff Wheeler:
> > > Whoever that person is that said something about "use next-hop-self"
> > > in this context, either you misunderstood them, or you shouldn't
> > > listen to them anymore. That has nothing to do with looking to see if
> > > your router knows about a route.
> > > 
> > 
> > 
> > This sounds like the OP wants to help the cloudfare guys who send the
> > following mail to DECIX/AMSIX (and probably other IX) yesterday.
> > 
> > > We're currently seeing a very large attack directed to our IP on AMS-IX
> > (X).
> > > 
> > > We request that all peers:
> > > 
> > > 1) Don't carry this route (X/22) in your backbone. (you can set
> > next-hop-self, etc). It'll save other security concerns and possible free
> > transit you're giving away to others.
> > > 2) Filter any traffic within to the AMS-IX exchange fabric (again,
> > 
> > X/22), except for your point to [multi]point BGP communications.
> > 
> > --
> > Kind Regards
> > Tobias Heister
> > 
> 
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