[j-nsp] PtP link over FR

Jesper Skriver jesper at skriver.dk
Thu Jul 17 07:24:16 EDT 2008

Let me guess, on Cisco Router A you got an ARP entry for Cisco
Router B's address when you put a Cisco router in the middle, as
the Cisco router has proxy-arp enabled by default.

Or to put it more clearly the IP addresses used FR p2p pvc is a
subset of the IP addresses used on the link between Cisco Router A
and Juniper Router.

Or on Cisco router A you have a static route without a next-hop address
to the IP subnet used on the FR link

In either case it's a mis configuration, that gets
'saved'/'hidden' by the fact proxy-arp is enabled by default on the
Cisco router.


On Thu, Jul 17, 2008 at 04:06:31PM +0500, Farhan Jaffer wrote:
> Hi,
> There is an interesting situation, let me discuss the scenario first,
> Cisco Router A ----(same n/w) ---- Juniper Router -----(FR
> point-to-point pvc) ------- Cisco Router B.
> PVC is Active & point to point connectivity is OK. But the ping
> response from cisco router A to B via FR is unreachable & vice versa.
> however if i replace Juniper router with Cisco Router, it works fine.
> Is there any IP forwarding like thing? or any other problem.
> Thanks very much in advance.
> -FJ
> _______________________________________________
> juniper-nsp mailing list juniper-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/juniper-nsp


Jesper Skriver, jesper(at)skriver(dot)dk  -  CCIE #5456

One Unix to rule them all, One Resolver to find them,
One IP to bring them all and in the zone to bind them.

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