>I don't buy this argument at all. The router knows about the /64 prefix only, unless are you talking about the ND cache? How does your router know which devic

>I don't buy this argument at all. The router knows about the /64 prefix only, unless are you talking about the ND cache? How does your router know which device to route a specific address? It can't possibly be broadcasting any incoming packet to all devices. >Furthermore, let's say you can fill up your route table somehow. What prevents the same thing from happening to the NAT state tracker? NAT has specific logic to handle dead connections. UDP connections typically time out if there's no activity within 2 minutes, and TCP within 10-60 minutes. Under typical usage situations you're unlikely to hit those limits, however consumer routers were known to choke on too many connections, eg. from torrenting. There's no similar mechanism for ipv6 privacy addressees. The closest is a dumb expiration timer (ie. temp_valid_lft), but that means it can only drop addresses without regard for whether it's active or not, causing issues for long lived connections (eg. ssh). None of these are impossible problems to solve. There's clearly enough computing power on routers to track each and every connection, so it should be possible to implement better tracking of privacy addresses, but that doesn't mean it's happening today. The same applies to browsers using a different address for private browsing. However "it can theoretically be fixed" isn't a valid response to the sad state of ipv6 privacy today. It's entirely reasonable for ivp4 holdouts to refuse ivp6 until these issues are fixed. >HTTP cookies are enough for that (tracking sessions). No amount of Layer 3 tricks like CGNAT or IPv6 privacy extension will fix it. This is false. Third party cookie tracking doesn't work on Firefox anymore because they enabled first party isolation by default a few years ago. Chrome is planning to do the same, but regardless users can already opt into it. >I assume you understand CGNAT sessions are logged? Irrelevant. If ISPs wants to log your CGNAT sessions, they can also log your ipv6 traffic.