All things related to multicast

["David Farmer" <>]

On 4 Sep 2003 David Farmer wrote:

> A BGP BOGON route like described on the web page you pointed 
> to: http://www.cymru.com/BGP/bogon-rs.html  Would work for 
> BOGON sources, Multicast NLRI routes point to a null,  then a 
> BOGON source should cause a packets to fail RPF, both for traffic 
> and MSDP I think.  But, I don't see how this can do anything based 
> on Group Address. 
> 
> This could very well be a good thing to do as well, but I don't see 
> how it can accomplish anything for BOGON Groups.  Which only 
> leaves hand built access lists I think.  Someone PLEASE tell me I'm 
> wrong :-(

Thinking through this some more, I think the standard unicast 
BOGON filter at the web site would cause BOGON sources to fail 
RPF, without needing a Mulitcast-NLRI route.  Therefore, the 
BOGON filters described will Blackhole unicast traffic going to 
BOGON destinations and any multicast traffic or MSDP BOGON 
sources.  If a router did Unicast-RPF, then it would also Blackhole 
any unicast from a BOGON source. 

But as I said above, I don't think this technique can't do anything 
for BOGON (Reserved) Multicast Groups.

> If bigger brains than mine figure out a way, I'd be willing to write a 
> dratf if no one else is.

Any ideas?

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