Hetzner now provides IPv6 only dedicated servers

Re:Hetzner now provides IPv6 only dedicated servers by profmonocle on Tuesday December 07, 2021 @09:57AM (#29473059)

Typically, a /64 in IPv6 is one subnet. You're not really supposed to subdivide networks beyond that point. The first 64 bits identify the network, the last 64 bits identify the host. Under this design, if you only assign a /64 per server, that would mean you couldn't have multiple networks on that VM (which you'd want for something like Docker.)

However, this principle isn't really enforced on a technical level. Only some standards such as SLAAC actually require the network to be a /64, and since SLAAC isn't really relevant for servers, most cloud providers have been relatively stingy with their IPv6 allocations - at least compared to what RFCs actually recommend. (Which would probably be a /48 per customer, per region.)

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Re:Hetzner now provides IPv6 only dedicated servers by mindslight on Tuesday December 07, 2021 @10:58AM (#29473925)

I appreciate the push to expand address allocations a bit, so that providers aren't charging a monthly fee for every /128 and the like. But /64 seems like ridiculous overkill. Even for a premises network connected to an ISP, the optimal thing to do is to continue NATting to hide information about your network. Privacy wise I'd rather have 2^16 separate /128's scattered throughout a provider's address space, than a single /64, which will inevitably be treated as a single address by the surveillance industry. Ultimately discrete public addresses are really only needed for services, and the services I want to share are few and enumerable. At this point I do more work making sure individual nodes aren't fully connected (eg Internet of Shit) than making services reachable.

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Re:Hetzner now provides IPv6 only dedicated servers by profmonocle on Tuesday December 07, 2021 @11:19AM (#29474286)

> /64 seems like ridiculous overkill

The idea behind the /64 minimum was to make auto-configuration easier - you could just stick the layer 2 ID (i.e. the MAC address) in the second half and not have to worry about collisions or stateful assignment system like DHCP. Remember that IPv6 was designed in the mid-90's, so both of these decisions seem silly now - using the MAC would be a serious privacy issue (modern operating systems use a random ID which changes frequently) and DHCP is very mature.

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Re:Hetzner now provides IPv6 only dedicated servers by mindslight on Tuesday December 07, 2021 @11:33AM (#29474545)

Yeah I was going to touch upon that. I understand where they were coming from design wise (apenwarr's post is fantastic for that - https://apenwarr.ca/log/20170810). Privacy extensions mainly seems like doubling down on an unworkable idea. I can see the hypothetical benefit on a shared network, where say a coffee shop has a /64 and you can have every single app looking like a separate device on that network to an outside observer. I just foresee the inevitable future where IP surveillance databases contain information like "this /48 hands out /64 to each end user, so treat it as one entity", rendering those extra bits as a mere liability to be mitigated.

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Re:Hetzner now provides IPv6 only dedicated servers by nightpool on Tuesday December 07, 2021 @11:44AM (#29474755)

Sure, but as the ancestor comment mentions, SLAAC has no relevance for the use-cases people in this thread want more then 64-bits for (e.g. Docker sub-networks). Since your Docker containers don't have "MAC addresses", there's no reason that you need to use 64 bits specifically to configure them. Your container runtime is perfectly positioned to assign IP addresses and subnets however it chooses to. Assigning a /72 to each container is perfectly fine.

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Re:Hetzner now provides IPv6 only dedicated servers by daneel_w on Tuesday December 07, 2021 @11:02AM (#29473993)

> "You're not really supposed to subdivide networks beyond that point."

Why not? Does it result in technical problems? I know very little about IPv6 (but I know that a /64 is an absurdly large network).

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Re:Hetzner now provides IPv6 only dedicated servers by fuzzy2 on Tuesday December 07, 2021 @09:57AM (#29473055)

A /56 + prefix delegation would enable IPv6 VMs without any dirty hacks.

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Re:Hetzner now provides IPv6 only dedicated servers by detaro on Tuesday December 07, 2021 @09:58AM (#29473081)

... giving each VM one IP out of the /64 is not a "dirty hack". I guess if you want to do complex networks between the VMs it'd help a bit? Still, /64 is IMHO a good default for single machines.

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Re:Hetzner now provides IPv6 only dedicated servers by fuzzy2 on Tuesday December 07, 2021 @10:48AM (#29473736)

Traffic for any of the addresses in the /64 arrives at your server’s "external" network interface. Is there any non-hacky way to forward this traffic to an internal virtual network?

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Re:Hetzner now provides IPv6 only dedicated servers by profmonocle on Tuesday December 07, 2021 @11:11AM (#29474162)

You just create a route for it, same as you would with any size network. Linux allows you to create routes for IPv6 prefixes longer than /64 without any issue. On AWS I have a VM with a /80 routed to it, which I have divided into multiple /96's internally. It works fine.

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Re:Hetzner now provides IPv6 only dedicated servers by sumtechguy on Tuesday December 07, 2021 @10:01AM (#29473124)

I know you are being funny. However, it does make me think hmmm... Is there any advantage/disadvantage to not handing out something like a /120? Or is there something else at play like in the way auto discovery is working? I am not familiar enough with it to say.

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Re:Hetzner now provides IPv6 only dedicated servers by detaro on Tuesday December 07, 2021 @10:08AM (#29473218)

Yes, various pieces kind of assume that smaller networks than /64 are not a thing, e.g. SLAAC, one of the mechanisms to distribute IPs.

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Re:Hetzner now provides IPv6 only dedicated servers by davidmurdoch on Tuesday December 07, 2021 @10:03AM (#29473150)

I have a /64 from my ISP and I want to run a few VLANs on my home network but I can't subdivide the /64 any further using my business class (TP-Link omada) router's controller. Maybe there are similar limitations in place here?

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Re:Hetzner now provides IPv6 only dedicated servers by edm0nd on Tuesday December 07, 2021 @09:54AM (#29473026)

First thing I can think of is spam and abuse

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Re:Hetzner now provides IPv6 only dedicated servers by profmonocle on Tuesday December 07, 2021 @10:01AM (#29473129)

If an IPv6 spam filter is working on a per-address basis, it's never going to work. The smallest allocation you can get from a RIR is a /48. Even residential ISPs give at least a /64. You could use a different address for every email and never run out.

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Re:Hetzner now provides IPv6 only dedicated servers by formerly_proven on Tuesday December 07, 2021 @09:58AM (#29473092)

Good luck sending emails with IPv6.

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Re:Hetzner now provides IPv6 only dedicated servers by BenjiWiebe on Tuesday December 07, 2021 @10:05AM (#29473178)

I do it already. Well, both IPv4 and IPv6. There's a decent number of IPv6 capable MX's out there, the most prominent being GMail.

If you were meaning IPv6-only then yes that would be pretty bad.

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Re:Hetzner now provides IPv6 only dedicated servers by profmonocle on Tuesday December 07, 2021 @10:03AM (#29473151)

It works fine with Gmail. And since G Suite is so widely used, tons of domains can send/receive mail over IPv6 just fine.

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Re:Hetzner now provides IPv6 only dedicated servers by vaylian on Tuesday December 07, 2021 @10:03AM (#29473153)

Why should that be an issue?

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Re:Hetzner now provides IPv6 only dedicated servers by erinnh on Tuesday December 07, 2021 @10:56AM (#29473882)

Some mail-admins will downgrade IPv6-only MX servers reputation-wise, due to the limiting/cost-increasing factor of IPv4 Addresses.

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