The mystifying 224.0.0.9 IP

[dcoronel]

I'm in a lab environment which consists of 2 routers and a station connected to each one for simulation purposes.

While debugging IP packets, I came accross the 224.0.0.9 IP address that was showing up every once in a while. I could not understand where it came from.

After a few minutes, I did a quick search on the internet for it and found the information I was looking for. I read that 224.0.0.9 was the IP that RIP v2 uses for multicasting its architecture.

What is weird is that I can't ping that address from the routers but I have no problem to do it on the stations. Can anyone tell me how this happens?

Thank you very much.

[ruwhite]

You should be able to ping 224.0.0.9--if any routers or other hosts are listening to this (have ripv2 configured), they should respond.

Russ

[juchen70]

Should respond?

I don't think so.because the multicast address map to a L2 multicast address directly,and only respond for special packet.Routers or hosts which have RIPV2 configured will drop the echo packet.I think.

[xavierchang]

That's incorrect. Cisco routers will definitely respond to a multicast ping. Hosts may or may not depending on the implementation, but should.

[zaziz]

Hi,

DO you have RIPv2 enabled on the interface.

do show ip interface and see if is joined to this multicase address.

When you ping from the station does both routers reply or just the one that has RIPv2 enabled?

When you ping from the router, only those devices will reply which have joined this multicast address. If this router is the only guy joined then no one else should reply.

Hope this helps

Zaheer