Monitoring GRE traffic with Netflow

Unanswered Question
May 24th, 2007


I have a GRE tunnel between an 3660 and a 3725. Under this tunnel there are many routers from SP, that we not even can see.

The problem is that at Netflow it shows me only a high GRE traffic, giving me only details if using Nbar but still like that loosing all of informations available at Netflow reports (Conversations, source, etc).

So, does anybody knows what should be configured at routers to enable netflow detailed informations of GRE tunnel?



I have this problem too.
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Can you supply a sample configuration.

I assume you have setup the following


ip flow-cache timeout active 1

ip flow-cache timeout inactive 15


ip flow-export source FastEthernet0

ip flow-export version 5

ip flow-export destination 9996


Per interface

ip route-cache flow

Sorry to state the obvious

luiz.alexandre.... Fri, 05/25/2007 - 11:47

ip flow-cache timeout active 5

ip flow-export source Loopback0

ip flow-export version 5

ip flow-export destination [Server IP] 9996

interface Tunnel0

description tunnel vers rct2sin2

bandwidth 27000

ip address x.x.x.x x.x.x.x

ip mtu 1472

ip nbar protocol-discovery

ip route-cache flow

ip tcp adjust-mss 1432

load-interval 30

These are my confiurations and the router is a 3660.




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