On: IPv6-only Virtual Servers

[bbrks]

Genuinely curious, why would a cheap virtual server ever need 4 billion IPv6 addresses?

Why not just give out a /64? (254 addresses) which is the minimum amount of addresses you can assign in IPv6.

[specialp → bbrks]

A /64 in IPv6 is 2^64 IP addresses (it is 128 bit). 256 IPv6 addresses is /120. The simple reason why they do not give smaller blocks is the VPS company themselves are assigned a minimum of /64 for network purposes. That means they have 4 billion blocks of 4 billion IPs so why be stingy :)

[dragonwriter → specialp]

> The simple reason why they do not give smaller blocks is the VPS company themselves are assigned a minimum of /64 for network purposes. That means they have 4 billion blocks of 4 billion IPs so why be stingy :)

Well, you know, they might end up having half the population of the planet buying servers, and then they'll be sorry they didn't give out smaller alotments...

[marcosdumay → dragonwriter]

They'll be sorry because they'll have to ask another block from ICANN? They don't look THAT hard to deal with.

They have an entire IPv4 space of IPv4 spaces to distribute, but that's still a ridiculously low amount near the total number of IPv6 addresses.

[eknkc → dragonwriter]

If they give everyone their own /64 subnet, it would still be like there were 4 billion of entire ipv4 address spaces available.

Given that the planet can run on a single ipv4 space right now, that's an awful lot to run through.

[stephengillie → eknkc]

2^32 ought to be enough for anybody?

[soneil → bbrks]

It looks like they're assigning a /96. /64 gives you 18 billion, billion addresses.

/64 isn't the minimum you can allocate (especially to a single host), but it's a recommended minimum for a network

[zAy0LfpBZLC8mAC → soneil]

No, it's not really a "recommended minimum", it's the size of the allocation for a local network segment, and that is because stateless autoconfiguration uses the last 64 bits of the address, and thus doesn't work with smaller subnets - and making the allocation for a local network segment larger doesn't make sense, as autoconfig can't use it anyhow (and you certainly won't have more devices either).

The recommended minimum for "a network" in the sense of an allocation assigned to a different administrative entity is a /56, so that multiple network segments can be set up without any further administrative overhead and without incentivizing network idiocy like NAT that's been holding us back with IPv4 for far too long already. Unfortunately, many providers seem to not have gotten the memo, allocating all kinds of idiotically small networks, thus essentially breaking IPv6 before it even got adopted ...

edit: I guess I should mention that providers themselves tend to get a minimum allocation of a /32 from their NIC, so they can assign 16 million /56 without running out of addresses (at which point the income generated from 16 million customers presumably should be more than enough to pay for another /32). They are simply majorly wasting address space by not allocating it ...