[hylaride]

I'd like to agree with you, but IPv6 had such a classic case of suffocation by committee during its birth that I doubt it would have been pushed by such a situation. IPSec was mandated in the original IPv6 RFC, for god's sake. That alone delayed a lot of work in implementing it as crypto code needed to be integrated into kernels, which was not common in those days. That's to say nothing about the fact that IPSec is loosely defined enough that setting it up between different vendors is always an adventure - adding support to an IP stack was a big headache (I followed OpenBSD at the time they were integrating IPv6 in the early 2000s and there was a lot of hard problems around compatibility).

Header integrity was so far off of consideration during IPv4's implementation because the internet was a dozen universities and DoD sites that it was overkill (and possibly a waste of limited CPU cycles at the time).

What's far more likely to have happened is that we'd see more proxies instead of NATs (SOCKS, etc). I don't think that'd be better than NAT.

[graealex]

It's funny that you mention IPSec, since that would have made most of the application-level encryption we see today obsolete. They did have good intentions, and if it was widely accepted, it would have meant that barely any applications would have had to deal with the details of encryption, including the ever-looming possibility of doing it wrong (doing encryption right is hard!).

Now we have a slew of protocols that either implement TLS, or roll their own custom thing, or have X-over-HTTPS protocols, including SSTP and DoH.

[hylaride]

IPSec was far too complicated, loosely defined, and over-engineered to have ever been widely accepted. Any host verification would need to involve application level verification anyways to make sure the other end is who you expect. So your browser would need to verify the encrypted tunnel is in face connected to google, or whoever. There’s a reason SSL/TLS is done at the application level.

[api]

There's some history I'm not aware of here. I didn't know just how bad the V6 second system committee shitshow was.

Today V6 has been stripped down almost to what it should have been: bigger addresses, then stop. All that's left to get there is to deprecate SLAAC or make it optional.

[kstrauser]

SLAAC’s awesome, though. It’s one of the good parts we definitely want to keep.

[hylaride]

SLAAC is awesome, but DNS support in it didn't show up until much later. The result is a mish-mash of DHCPv6/SLAAC support (and android famously doesn't support DHCPv6 at all and windows only supported DHCPv6 until windows 10).

[api]

Let's say your ISP gives you a /64. Now you have to use V6 NAT... or assign a /96 internally. SLAAC won't let you do that.

That, among other things, is a problem. SLAAC is too limited.

You can use DHCPv6 but then you can't use Android because Android, and I think they're alone here, stubbornly and dogmatically refuses to implement it. I guess you could go around and statically assign V6 IPs to Android devices, or run NATv6 with SLAAC for those and DHCPv6 for everything else, but that's annoying as hell.

[labcomputer]

Then your ISP isn’t following the RFCs. You might as well ask what you would do if you ISP gives your router a 17.0.0.0/8 address via DHCP.

These are completely invented problems in your head. SLAAC can absolutely advertise a single /64 internally. It can advertise any /64 you tell it to.

DHCPv6 can absolutely respond with DNS servers (and nothing else) in parallel. Configuring your SLAAC daemon to tell clients to get DNS servers via DHCPv6 is a 15 minute exercise with google.

[api]

> Then your ISP isn’t following the RFCs.

Oh, summer child...

[kstrauser]

Android's right on this one (and I don't own an Android device that I know of, so this isn't me fanboying them). TBH ISPs that hand out /64's shouldn't be allowed to say that they support IPv6 because it's a completely non-standard — not as in "uncommon", but as in "violates the documented standards" - setup.

[zrm]

Users have poor leverage over ISPs. A lot of them still don't support IPv6 out of unmitigated laziness. If they provide it but violate the standard there isn't much you can do about it, so what the standard is really doing is preventing you from mitigating it.

The standard requiring an entire /64 for SLAAC is also just a poor design.

Suppose your ISP is doing the right thing and giving you at least a /56. You have a complex network with your own subnets and you're not sure how many you'll need in the future, but the spec says you only have to give each one a /64 and that seems like plenty, so the person setting up the network does that. Time passes and you get devices in various subnets with fixed addresses you need to stay fixed. Then you want to hook up a VM host or anything else that wants to further subdivide the address space, but the spec says you can't even though there are still scads of addresses. And for what, so they can use EUI-64 which in practice is only 48 bits anyway and is effectively deprecated because it's a privacy fail?

[0x457]

Wait, what's not standard about /64?

[hylaride]

Strictly speaking, it's perfectly standard and you can subdivide it (manually). However, for a variety of reasons subnetting smaller than a /64 is difficult and not supported at all via SLAAC (because the host portion is derived from the MAC which is already 48 bits, plus other overhead). So if you want to split up a /64 from your ISP, you're limited to manual configuration, DHCPv6 (and no android support), or other ways:

https://version6.ru/en/dividing-the-indivisible

If you're just dealing with a single network at home, a /64 is otherwise fine. But there's a reason the recommended handout from ISPs is a /56; the inventors of IPv6 (or more specifically SLAAC) just didn't take into consideration how intransigent big telecoms would be.

[kstrauser]

RFC 3177[0] says:

"In particular, we recommend:

- Home network subscribers, connecting through on-demand or always-on connections should receive a /48.

- Small and large enterprises should receive a /48.

- Very large subscribers could receive a /47 or slightly shorter prefix, or multiple /48's.

There was some walking that back in later RFCs, arguing that home customers could get by with just a /56.

[0] https://www.rfc-editor.org/rfc/rfc3177.txt