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Re: Sinkhole Architecture
On Fri, 29 Apr 2005, Howard C. Berkowitz wrote: > > At 1:34 PM +0000 4/29/05, Christopher L. Morrow wrote: > >On Fri, 29 Apr 2005, Howard C. Berkowitz wrote: > > > >> > >> I've seen some Cisco security presentations that include sinkholes > >> composed of an ingress and egress router, interconnected with a > >> switch. The switch provides access for tools such as packet > >> analyzers, IDS, routing analyzers, etc. The multiple routers also > >> provide more horsepower for inspection, filtering, and > >> overhead-imposing measurements such as NetFlow. > > > >the multiple routers could just be a way to get a MAC to the ingress > >router for delivery over the ethernet... a sun/linux/bsd/*unix box might > >provide the same function. (please logging, analysis, ids, flow > >collection) > > The architecture described doesn't have the two routers treating the > Ethernet as a destination: > > SinkholeIn--->Switch------>SinkholeOut > | > | > analyzers hrm, 'sinkhole' to me always means 'hole' not 'sinkpassthrough'. normally if we do this we just drop the traffic in a hole we can look at, then release the route later after analysis. With the 'in/out' concept you have to provide a manner to tunnel away from the hole, else you end up looping back through it indefinitely (or so it would seem). > > > > >> > >> I am unclear about the BGP relationship between the two routers, > >> which are meant to be treated as one subsystem. The ingress router > >> (with respect to the outside) clearly has to have its BGP isolated > >> from the rest of the AS, so it can't be part of the iBGP mesh. > >> > > > >why can't it be part of the ibgp mesh? I'm not sure I see why that would > >be BAD, aside from it bouncing under load and affecting all ibgp > >neighbors... so, aside from route-churn and neighbor setup/teardown churn > >what other reasons? > > The most basic is whether I am diverting a maliciously inserted route > to it from the edge router. uhm, so you put a /32 into the sinkhole all traffic to that destination in your network heads there. What 'maliciously inserted route' are you talking about? something a customer of yours sends you?