IPv6

I’ve just played with IPv6 for a few minutes – AFAICR it’s the first time I’ve ever done so. I’m going to have to learn more, because IPv6 is here and we’re all going to have to use it. Eventually.

My broadband supplier is BT. The Smarthub (not nearly as smart as I’d like, but that’s another story, and for a different thread!) shows me IPv6 addresses for itself, the WAN and the LAN, but only shows IPv4 addresses for the LAN devices. However, the Linux box has IPv6 working, of course, and I can use ping6 to ping itself, the Smarthub, and a couple of external addresses (ipv6.google.com and bbc.co.uk).

Dynamic DNS gives me an external IPv4 address, but I can’t ping the same URL for IPv6.

I browsed from the Linux box to one web site that showed the IPv6 address that I had connected from, and it was indeed one of the addreses listed by “ipconfig -a”. So the Linux box must have been using IPv6 for years without me realising it – which is of course how it should work.

Who else has got any of their LAN working via IPv6?

Who else has any IPv6 status or configuration pages on their router?

What other tests have you done?

I think I ought to be able to “ping6 fe80::ac75:99ef:9466:e3c2” (this appears to be a correct IPv6 address on the LAN), but I get “Invalid argument”. Anyone know why? I seem to get the same result for any legit local IPv6 address.

Edit: should’ve web searched first. Any “fe80::” addresses need ping6 to have args “-I enp0s25” in my case, “-I ” in the general case. (Mine isn’t eth0.)

And I can ping my mobile phone via its link-local or either of its external IPv6 addresses, from the Linux box.

Dynamic DNS gives me an external IPv4 address, but I can’t ping the same URL for IPv6.

No, you won’t. Dynamic DNS is necessary because there aren’t enough IPv4 addresses to go around, so home users (such as we are) get the next address out of the pool. And if you’ve ever looked to see what address you’re on with mobile comms, it’s all running some sort of insane NAT setup. Also IPv4.

Additionally, you’ll need a DNS system capable of supporting IPv6 lookups. Normal IPv4 uses ‘A’ records. IPv6 uses ‘AAAA’ records. If there’s no AAAA record, there’s no IPv6 DNS entry.
Here are my DNS entries.

With IPv6, you have an IP address. That’s you. It’s fixed. Mine is 2a01:cb08:xxxx:xxxx::/56, which I think means I have 4,722,366,482,869,645,213,696 IP addresses?

You should notice that you have two IPv6 addresses. One of those is fixed (it is derived from your device’s MAC address), however this isn’t very good when it comes to privacy, especially considering that MAC addresses are allocated in blocks which can identify what sort of device you’re using. The Pi’s MAC begins b8:27:eb which is an address allocated to the Raspberry Pi Foundation. So anybody seeing that will know it’s some sort of Pi.
So Privacy Extensions were created (RFC 4941) which means that a device will generate a temporary random address (within your block) for a length of time, and that’s what the outside world will see. This random address will periodically change.

Who else has got any of their LAN working via IPv6?

Me. It had been languishing as an option for a while, and then one day when using my phone to read my blog (which shows you your IP address at the top right), it said “Hello” followed by a load of gibberish. An IPv6 address.

Who else has any IPv6 status or configuration pages on their router?

It’s an on/off toggle, which when on shows me my IPv6 block.

What other tests have you done?

Online IPv6 test. It looks like the Vonets can support IPv6 as a transport, but doesn’t understand IPv6 DNS. Honestly, I’ve not noticed. Websites just seem to work, and they may be IPv4 or IPv6…

should’ve web searched first

Yeah – useful isn’t it? The addresses you’re most likely to want to ping need to have an interface specified because “it doesn’t work that way any more”.

Apparently, you may also be able to use ping6 fe80::ac75:99ef:9466:e3c2%enp0s25 but this is getting to be a ridiculous amount of typing!

And I can ping my mobile phone via its link-local or either of its external IPv6 addresses, from the Linux box.

I’ve not tried. I don’t have anything with an easily accessible command line that supports IPv6. There’s the printer, my phone, and I think the tablet does IPv6 as well. My PC runs XP which sometimes struggles with IPv4. :-/ And RISC OS… is IPv4 too.

Dynamic DNS gives me an external IPv4 address, but I can’t ping the same URL for IPv6.

No, you won’t. Dynamic DNS is necessary because there aren’t enough IPv4 addresses to go around

It’s necessary for me, to give a URL that can be resolved to my home IP address, rather than davehigton.me.uk which points at my web site, which is hosted for me. BT don’t give me a static IP address – they charge a lot extra for it – so it’s dynamic in that it changes. My router (supplied by BT) has built-in support for DDNS from a very short list of companies.

But, as you say, the DDNS service I’m using is clearly an IPv4-only service. It’s free, and their next tier costs far more than I’m prepared to pay, bearing in mind how infrequently I use it.

Same here – I use No-IP for the heyrick.ddns.net address; which is my Pi (home server). Some stuff (like Manga updates) I drop there, as it’s less of a faff than uploading to the main website.

I don’t think Orange provide static IP, I think that’s reserved “for business customers”. Us normal people get dynamic IP, which let’s face it, is perfectly okay for the vast majority of their customers. For people like us, there are services like No-IP.

I’m not actually sure how you’d go about setting up a DNS record to an IPv6 IP address hosted on a domestic broadband account.

their next tier costs far more than I’m prepared to pay, bearing in mind how infrequently I use it.

It’s more than I need, too. If I want to provide a ‘name’ to point to my box, the ability to have dozens is…. why? If a person is running that sort of setup, they probably ought to cough some cash in the direction of somebody like OVH to have a proper hosting service with a real domain name.

So anybody seeing that will know it’s some sort of Pi

I’m considered weird at work¹ for knowing b8:27:eb for Pi and 00:09:fb for the bedside monitors.
Apparently you would also fit that classification. Who knew? :)

¹ Bear in mind that the people thinking that are in IT support

Update:

Livebox → System information → Internet
primary DNSv6 IP – none
secondary DNSv6 IP – none

Well, that’s why using IPv6 to look up IPv6 addresses doesn’t work. It’ll work if an outside service (like OpenDNS) is used, but not if relying on the ISP.
Bug, or not yet supported?