- When I connect my IPV6 refrigerator with its automatic inventory
system tracking every RFID-enabled carrot I use, won't I be making my shopping habits visible to all those annoying advertisers? Or, in other words, am I compromising my privacy? Actually, although such dissemination of information can be blocked by a correctly designed firewall, I suspect the "Free IPv6 DSL Modem and Router, Sponsored by <your-favorite-commercial-site>" that comes with your ISP contract, would err on the side of promiscuity
Set your refrigerator to fe80:0001:: and it's now only accessible on the local subnet. Quoting http://www.litech.org/~jeff/private/ipv6primer/html/ Two prefixes are set aside for link-local and site-local addresses.
site-local addresses are officially deprecated.
If you want a device to only be available locally - block the traffic to/from that device. Or block if from acquiring a public address and leave it as link-local only [most people will, I think, just choose the first options - like they do now when they want to block a device].