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A comment on IPv6 Is Hard. Parent comment

Re:IPv6 Is Hard by growse on Sunday February 16, 2025 @03:32PM (#43071394)
> If that's the only benefit of IPv6, it doesn't sound worth it to me.

It's not the only benefit, as anyone who's tried to build a large network or merge two networks with overlapping address space will tell you.

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Re:IPv6 Is Hard by Spivak on Sunday February 16, 2025 @07:22PM (#43073344)
IPv6 doesn't actually save you because it presumes a cultural norm that people will use globally unique addresses for all their networks which, while now possible, I imagine many network engineers will use IPv6's private address space to avoid ever having to re-address their network on ISP changes.
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Re:IPv6 Is Hard by throw0101c on Sunday February 16, 2025 @09:01PM (#43074122)
> I imagine many network engineers will use IPv6's private address space to avoid ever having to re-address their network on ISP changes.

Except with 10/8 (or 172/12) everyone is using the same address space. How many network have a 10.0.0.0/24? What are the odds of a conflict for that?

But if you have an ULA FDxx:xxxx:xxxx/48 address space, what are the odds that all those x bits will be the same for any two sites? That's 40 bits 'entropy'. Much, much lower (notwithstanding folks doing DEADBEEF, BADCAFE, etc).

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Re:IPv6 Is Hard by patrakov on Monday February 17, 2025 @12:49AM (#43075616)
Not only that. Having private IPv6 addresses in the LAN is the easiest way to work with two ISPs and have fail-over. The other way is RFC8475, but I don't know of any implementation except my custom script on OpenWrt: https://forum.openwrt.org/t/ipv6-wan-fail-over-without-ipv6-...
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Re:IPv6 Is Hard by growse on Monday February 17, 2025 @02:34AM (#43076216)
I imagine the threshold of org size where they stop taking their prefixes from their ISP and just go get their own from the RIR is .... Not big.

Sure, some network engineers will try and design v6 networks as though they're v4, but everyone else will just go and get a squillion addresses from the RIR that's unique to their org and then just use/announce that.

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Re:IPv6 Is Hard by silon42 on Monday February 17, 2025 @04:19AM (#43076840)
What about home private network (for smart home, for example)?
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Re:IPv6 Is Hard by growse on Monday February 17, 2025 @04:24AM (#43076879)
Home networks don't usually have the problem of having to suddenly merge together with another, similarly-addressed network.

Nothing stops you getting a subnet allocated from your local RIR and announcing that on the internet, if you care about that sort of thing for your home network though. You just need a decent ISP.

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Re:IPv6 Is Hard by ninkendo on Monday February 17, 2025 @09:37PM (#43085515)
> Nothing stops you […] You just need a decent ISP.

I’ll just leave that there.

No, I can’t just choose to have a decent ISP. I live in the real world where there’s only one choice where I live, same as a rather large majority of people in the world.

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Re:IPv6 Is Hard by yyyk on Monday February 17, 2025 @12:52AM (#43075626)
'You should switch your working local networking stack so as to help the scenario where the company is bought and you may well not be working there anymore and it's someone else's problem. Or the scenario where the company buys a different company and very likely needs to investigate and remodel the other company's network anyway.'
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