[scurvy]

They all respond because I asked them for it. About half didn't upon turn up. It's super trivial for them to null route them or readdress in rfc 1918/4193 space.

Or are you referring to xconnects inside their network? That's up to them to work out and I've never seen a provider just abandon their network while under attack.

[alexforster]

You may want to reconsider. CoPP only goes so far, as we've learned the hard way.

[scurvy]

I don't run Cisco, but thanks for worrying about that. Also, stateless ACL's should protect against overrunning the control plane.