IPv6 Watch

Probably because /64 is the smallest recommended subnet size, and a /60 has “only” 16 /64 subnets within it.

[not OP, but hey…] There’s no need for DHCP with IPv6. Clients choose the last 64 bits of an address randomly. The address space is huge — zero probability of a duplicate address.

The first 64 bits therefore identify the network. If your ISP routes a /60 to you then you get to split that into 16x /64s.

That’s probably fine, but the IETF recommendation is to dish out a /56 to small sites and give them a /48 if they ask for it. ISPs usually have multiple /32s at their disposal.

It’s not about number of available addresses or networks. The joy of IPv6 is the addresses are so wide you can bring back hierarchical addressing. No internal routing chicanery is needed.

If your site has 64 buildings then a /56 lets you assign a /62 to each, with 4x VLANs in each building eg for printers, guest net, phones, lighting, admin, with even a subnet for each business function in the building.

IPv6 has Stateless Address Auto-Configuration (SLAAC) as preferred method for address assignment. This allows clients to generate addresses for themselves as needed. For that to work efficiently, the address space needs to be sufficiently large that collisions are unlikely even in larger networks. Because of that, it mandates a subnet size of /64.

More generally, a big difference in v6 is that you no longer have to plan subnet sizes at all. Whereas previously you'd carefully choose the next available address to minimize address waste, with v6 you can just assign the addresses in whatever way makes sense to you.

The idea is that there's SO much address space -- you should never need to consider a question like: "is /60 to /64 enough for all of my subnets?" when planning your network. Subnets should be created because they make sense from an organizational point of view. The amount of available bits shouldn't be a practical consideration.

Also, remember, NAT is highly discouraged, so you'll (maybe) eat up another subnet if you run something like Minikube on a laptop.

Do you mean Mobile IP? https://en.wikipedia.org/wiki/Mobile_IP (part of IPv6)

I would guess that the first two chapters would be useful.

Honestly, if your first thought isn't "oh wow, I would love to learn how to plan out IPv6 networks", it might not be worthwhile.

For home you probably care about SLAAC, PD, the standard subnet size of /64, and possibly the Link Local differences (more out of curiosity of what those addresses show up on your machines for than needing to know to do anything with it). Also DNS is going to have AAAA records instead of A records and reverse lookups use a different zone, the changes in DNS are pretty 1:1 translational for admins though. If you want to go full on v6 you'll want to read about NAT64 so you can still reach the v4 internet from your v6 only home network. Also take a look at http://shouldiblockicmp.com/ even if you don't go down the path of v6.

For applications programming you'll want to have a feel for the above, IPv4-mapped IPv6 addresses, and review link local again to in particular note how to encode the interface in a socket call (useful for configurationless cluster communication).

Most every other detail of IPv6 changes should only matter to those that write networking stacks or make routers.

For all of the above info I'd recommend just reading the Wikipedia article on IPv6. Most of these are straightforward wrote memorization of best practices or background reasoning things so it's not "read a book" worthy if you're not trying to do this for a living IMO (coming from someone who does networking for a living).

It's actually crazy how late this was. Because customers don't like to see forty surcharges, you have an incentive to bundle relatively cheap things most or all customers want.

What gets bundled and what doesn't is somewhat† a matter of company preference. And once IPv4 exhaustion was on the horizon, charging IPv4 separately made a lot of sense yet very few providers did it.

† The EU hates "hidden fees". If your product claims to cost €100 but actually there's no way to only buy the €100 product, you need "delivery" for €25 more because there's no practical way to avoid getting it delivered - that's not legal. Likewise if you claim it costs €100 but there's no way to pay cash, and all card payments have a 5% surcharge, you're going to either have to eat that surcharge, or advertise the price including the card surcharge.

The only NAT between most users and most sites are the users' modem/router combos, and those are pretty fast and reliable.

One less reason to take up gardening? /s

In what way would using ipv6 enhance your experience using the sites listed on the site?

Obviously, anyone already using this site can already afford IPv4

The site becomes reachable to IPv6-only hosts.

Some servers can work reliably with only IPv6, for instance, until you need to contact IPv4-only servers.

I would like my mail server to be IPv6-only, but that's not currently possible, for instance.

I wonder how many customers can realistically hide behind a single IPv4 (CGNAT), given that there are 65535 TCP/UDP ports.

I was referring to Hacker News' lack of support for IPv6, however it is nice to see that ipv6.watch does support it.

To elaborate: I feel that the irony comes from an apparent desire by this website's users towards supporting IPv6, as evidenced by a few articles about the topic on the first page today; Raising awareness of IPv6 support on a site that does not.

If you can reach the Steam website to buy a game and then you can't install it, because the site has IPv6 but the app doesn't, it is much worse.

Yes, that works.

I am not comfortable giving a container full control over the host network though. I have not looked into the security implications of it but I would expect it is dangerous for the host.

The problem with Docker is that assumptions of NAT and proxies are built-in quite deeply into the v4 networking functionality and defaults. With v4 it just exposes NATed rfc1918 space subnets to containers with a hardcoded prefix that's by default the same for all Docker installations in the world.

The sensible way to use it in the ipv6 world would be to give Docker its own globally routable prefix(es) acquired via eg dhcpv6 prefix delegation. The current manual prefix configuration is not how things should work in v6.

I’m mostly still annoyed about the colon. Come on, ip:port is a pretty widely used convention people! The number of parsing bugs I had to fix with the migration…

They could have at least let ipv6 only folks talk to ipv4 more easily. Something like 464XLAT maybe built in out the gate more? You go ipv6 until next hop is IPv4. If you are in IPv4 mapped address space translate to IPv4 there and continue.

it doesn't

None of that is actually true though?

> It simplifies aspects of address configuration

I assume this is referring to SLAAC? SLAAC is...fine. Most managed networks will want the extra control offered by DHCP though and DHCPv6 is currently in a much much worse state than DHCPv4. Also a single interface having at least 2, usually 3 or more (link-local, autogenerated, privacy) v6 addresses on the network is definitely not simpler in any way. Also clients still have not figured out which configuration methods they should actually support - Linux network managers generally default to SLAAC-only and DHCP needs to be explicitly enabled, for Windows setting managed flag in RA works, I believe. Android does not support DCHPv6 at all.

> network renumbering and router announcements when changing network connectivity providers.

Absolutely not. Network renumbering is a breeze when all you need to change is the public address of your gateway and the local network keeps the same local addresses. Prefix translation is awful and no firewalls have good tools to handle changing your v6 prefix.

> It simplifies processing of packets in routers by placing the responsibility for packet fragmentation into the end points.

With respect to fragmentation - yes, but overall this statement is blatantly false. v6 packet processing by routers is much much harder due to the variable length headers.

> The IPv6 subnet size is standardized by fixing the size of the host identifier portion of an address to 64 bits.

Ok, this one is true. Not entirely sure why the author considers this better, but sure, I'll agree.

This. It's liberating to assign a single IP to every service. You can move the IP around with the service, get rid of extra reverse proxies, SNI, etc.

I'd prefer it if I could really move around while keeping the IP, that's (among others) what yggdrasil offers.

You still need DHCP for more than one reason: 1. Prefix delegation 2. DDNS (DHCP server can register a client IP in DNS)

I've used SLAAC in my home LAN when used IPv6 ISP. Now I use IPv4-only ISP (in my area no ISP supports IPv6) and don't miss SLAAC at all.

Over the years I've used DHCP in many smallish LANs (<=100 hosts) and never had any problems with it.

At this point most of them do, but also require customers to explicitly opt-in. I think cloudflare is the only exception there, it won't even let you opt out unless you're on a paid plan.

Sort of seems like it doesn't matter who uses ipv6 on their servers, then. If ipv4 is mandatory, who cares that you COULD connect another way? Isn't the first step getting all clients able to use it?