All things related to multicast

[Bill Owens <>]

Is from MIT! Aren't you glad they're using so much multicast? Let's see what 
it is:

224.16.19.195   18.7.32.13 (w92-gen-arch-3.mit.edu) RP: 18.255.255.48
224.16.22.7     18.14.84.12 (m48-exterior-cam-2.mit.edu) RP: 18.255.255.48
224.16.22.13    18.14.84.11 (m48-exterior-cam-1.mit.edu) RP: 18.255.255.48
224.16.17.172   18.14.89.13 (m9-058-cam-2.mit.edu) RP: 18.255.255.48
224.16.27.229   18.14.245.38 (w7-100lb-cam-2.mit.edu) RP: 18.255.255.48
224.16.27.217   18.14.245.49 (w7-ext-cam-7.mit.edu) RP: 18.255.255.48

Oh, dear. Those look like security cameras. Perhaps someone didn't understand 
the concept of the organization-local scope, and decided they'd just use IANA 
reserved group addresses instead. 447 of them, by my count, out of a total of 
2025 SAs. The good news is that they don't appear to be leaking traffic, that 
would be really embarassing. As opposed to only being embarassing in front of 
network geeks.

BTW, I noticed this because I'm finally fed up with all the crap SAs (and 
traffic) floating around, and am starting to tighten down our MSDP filters to 
exclude the reserved ranges. I wasn't going to do 224.5.0.0-224.251.255.255 
because it's a pain to write it out in Cisco ACL format, but maybe I will 
make an exception thanks to MIT's example in this area.

Bill.