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IPv6 adoption statistics – Google (www.google.com)
submitted 6 months ago by to c/technology@lemmy.world
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[–] 8 points 6 months ago (7 children)

Doesn't a /64 already give me more than I'll ever use?

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  • [–] 5 points 6 months ago (6 children)

    An IPv6 subnet must be /64. Anything else breaks stuff. If you want a separate network for guests or IoT devices, a single /64 won't be enough because it can't be divided up any smaller.

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  • [–] 2 points 6 months ago (5 children)

    You can't subnet below a /64 at all? Or it just makes things like SLAAC/auto-addressing using the MAC address unusable?

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  • [–] 2 points 6 months ago (3 children)

    SLAAC won't work with a smaller subnet. Static addressing is not an option since your /64 is going to be dynamically assigned. That leaves DHCPv6, which won't work with any android devices or chromebooks.

    It would be best to just run IPv6 on one network if you can't at least get a /60.

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  • [–] 2 points 6 months ago (2 children)

    I'm a bit concerned about SLAAC's metadata leakage. Sending out many of my devices' MAC addresses to the world isn't exactly the best for privacy. My key devices like laptop and phone use MAC randomization, but I have a ton of other stuff that doesn't.

    That leaves DHCPv6, which won’t work with any android devices or chromebooks.

    Damn, that's a straight WONTFIX, too since 2014. Lots of religious argument in there, maybe I'm reading all that tonight.

    Thanks for answering my questions.

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  • [–] 2 points 6 months ago (1 child)

    Modern operating systems don't use the MAC address for SLAAC. They generate a completely random address. You can choose a stable address or a temporary one that will change frequently for more privacy. You can also use both, IPv6 allows multiple addresses on one device.

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  • [–] 1 point 6 months ago

    The only legitimate v6 prefix smaller than /64 is /127, to be used for point to point links, similar to /31’s in v4, but these aren’t processed for routing outside of the boxes the link is configured on.

    The concepts of addressing for v4 and v6 don’t map 1:1.

    From the perspective of the internet, and any properly configured routing infrastructure, they should only ever be interested in the first 64 bits when routing, the second 64 should be exclusively the domain of the last segment. It’s like inserting an additional type of addressing between the routing portion and the protocol port.

    You kind of have this with v4, but it’s variable, particularly since CIDR shot the v4 address classes in the head, so the equipment had to be able to process the entire address with every routing lookup and other functions.

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