Autorp relies on two control groups - 224.0.1.39 and 224.0.1.40.  Both
groups operate in dense mode.

'sh ip mroute' on every router better be showing you the two control groups
(224.0.1.39 and 224.0.1.40) or the network is broken.  That's the first
thing I'd check after making sure I didn't forget to enable pim on some
interface.  

Again, they are dense mode groups.  So if you are in sparse-mode, you need
some mechanism to permit their forwarding and that mechanism is autorp
listener.

Make sure in your testing you've got a network topology that doesn't just
consist of routers directly connected to the mapping agent.  Those two dense
mode groups work just fine link local (look at L flag in mroute entry) even
if every interface is configured for sparse-mode.  That might be why it
appears to you that things always work regardless of the presence of rp
listener.  Expand the topology a bit, and the routers two hops removed will
show you a borked mroute table.

Hope it helps.  

On Wed, Jul 15, 2009 at 5:14 AM, Bodnar, Edward
<[email protected]<mailto:[email protected]>> wrote:
OK I need to ask this question one last time but in a different way.

Lets say I am working through Multicast and I forget to put AutoRP listner
on. What would nto be working and how could I tell that it's not working.

Example.  I need Autorp listner but forget to put it on.
I do sho ? and realize that it's not working and I need to add this command.


Can anybody help.   Cant believe I am still frustrated over this command.
Everything just seems to work with it on or without it.

*********

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