Reply to post: Re: Privacy issues with IPv6?

IPv6 growth is slowing and no one knows why. Let's see if El Reg can address what's going on

Jamie Jones Silver badge

Re: Privacy issues with IPv6?

Does the standard still call for the mac address to be included in the packet? Maybe that's why nobody wants it?

Whilst what you are describing would literally be true in some cases, the case you describe is actually when the MAC is incorporated as part of the hosts IP adddress. - There is no "MAC field" in an IP packet.

Someone had this bright idea to say that a local lan has to be at least 64 bits wide, so that any host can guarantee itself a unique IP address without needing to use DHCP6 - simply by setting the 64 bits to contain the MAC address, and the rest of the address set to the subnet address.

Ugly, horrible, stupid. What happens if someone intentionally manually sets their IP to match what yours should be? There are many other ways to do it (e.g. DHCP6 which - as its name suggests - is the IP6 version of IP4)

So, it only applied to stateless IP configuration - there was never any such leakage if you just apply a normal address statically.

This is my only criticism of IP6, and it turns out to be administrative rather than technical (if you ignore statless addressing (SLAAC) as a requirement)

In my opinion, this basically wastes 56bits - meaning they could have just as well made IPv6 72 bits instead of 128.

Anyway, sod that. SLAAC will never exist on anything I control if I have any say in the matter. If I have 2 neighbouring IP6 lans, I'll be buggerred if I'm going to apply for a second /64 and if It's a "router -> WAN <-> router" setup, it will be a /126 - far easier and more efficient.

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