Owen DeLong (owen) writes:
But, Jeff, if the router has a bunch of /24s attached to it and you scan them all, the problem is much larger than 250 arp entries.
I think that's what Phil was getting at.
And so did Joel. If you've got a crapload of VLANs attached to a box, and you're routing these for customers (say, virtual firewall instances), you'll see this easily. I do understand the argument that sweeping a /64 will mean more L3->L2 lookups for directly connected subnets than in v4, but the problem domain remains the same, and I think it's been already explained here that there are various strategies to mitigate this. Additionnally I believe the size of typical recommended IPv6 space will probably discourage idle scanning, though this may change as the resources available increase, as Joe G. pointed out. If it does not, we'll have to address it if the existing mitigation techniques aren't sufficient. Phil