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Comment by nvarsj | Hacker News Reader

I'm happy that my ISP gives me a /29 ipv4 block :).

An example of a real world effect is one of the largest fibre ISPs in the U.K. They are the only provider afaik to assign users internal IPs, which is then NAT'd. This then gets NAT'd on the router again - double NAT, woohoo! :) I know they desperately tried to get enough public space for all their customers, but were unable to buy a large enough space for it, so were forced into this position.

Interestingly, the U.K. has at least two /8 ranges that aren't even advertised on the public internet, owned by MoD (25/8) and Department of Work & Pensions (51/8). That's 32 million addresses unused as far as anyone can tell from the outside.

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> the largest fibre ISPs in the U.K

> so were forced into this position.

Well it's not like they could have deployed IPv6 (with NAT64) instead (/rant). Most ISPs around here (France) provide IPv6, some of them since like 10 years ago.

Not supporting IPv6 today is just ridiculous, and I've jumped ship† regularly during those 10 years, explicitly mentioning IPv6 (lack thereof or unsatisfying support) as the reason when cancelling. I understand that not everyone has this chance (due to choice availability) to pressure their ISPs, but seriously they weren't forced: they dug themselves into this hole.

† One of them even dropped a previously perfectly functional IPv6 support for me purely due to a contract update and argued it wasn't possible to bring it back. Seriously.

Huh. Does the DWP really need 16 million addresses just to deny people benefit payments?

They started selling them off: http://www.bbc.com/news/technology-32826353

Question - given that they've condemned you to an awful carrier-grade-NAT, do they at least support IPv6?

I'm of the opinion that this is probably the future for all residential internet users - ISPs that put everyone on an IPv4 NAT so that grandma can still get her hotmail and yahoo, while hopefully providing unencumbered IPv6 access for everything else that requires a real network connection.

That's the world I'm in. Carrier NAT for IPv4, fully working routable IPv6 as designed.

Unfortunately this still screws me over because nobody who I might want to connect to my home network has IPv6 yet.

You might be surprised how much of your traffic already goes over ipv6. Much of your Google and Facebook traffic, for instance.

But then a lot of software still only supports IPv4, e.g. Dropbox or Resilio Sync. In the latter case that gives me some serious headaches, it has the tendency to open a lot of connections at once. I think my ISPs DS-Lite uses some quota, because when I have sync open on more than a certain number of devices, IPv4 connections start getting dropped and IPv4 is basically unusable for 5-10 minutes. I am pretty sure it's related to DS-Lite, because it doesn't happen to devices that are connected to a VPN.

It would help me a lot if all (mostly proprietary) software vendors would finally start supporting IPv6.

Sure but that's all outbound. What matters to me more is what can connect inbound e.g. p2p apps and most of them do not really do ipv6

AAISP and Sky are the only two ISPs to provide IPv6 in the UK. BT Consumer have been promising it "real soon now" for the last few years, and the rest of the ISPs are sitting on their hands.

BT already has a limited IPv6 rollout in progress[1], but the hardwares a big limiting factor (the early hubs definitely cannot manage it).

[1] http://arstechnica.co.uk/information-technology/2016/08/sky-...

I was pleasantly surprised when I was given a global IPv6 address at my parents house (where they use Sky). I had no idea they'd already managed to do it, and was expecting them to drag their feet for as long as possible.

AFAIK, Sky has rolled out IPv6 to all staff now. Except, well, it's enabled at a cabinet level (AIUI) so everyone served by the same cabinet has IPv6 now.

Sky gave an interesting technical presentation to the UK IPv6 Council in June about the roll out[1]. There is another presentation scheduled for October if you want to know more[2].

1: http://www.ipv6.org.uk/wp-content/uploads/2016/07/UK-IPv6-Co... 2: http://www.ipv6.org.uk/blog/

I got the nice surprise of getting an IPv6 block with BT recently, everything works as expected. They are finally rolling it out, it seems.

BT gave me an IPv6 address a few months ago - bit of treat for running non-ISP VDSL equipment, taking advantage of it early!

And Zen Internet

Yep Zen is great! That's where I got my /29 from. They also fix issues very quickly - when netalyzr complained that my ISP couldn't handle fragmented udp packets, I let them know and they fixed it within a few days.

Some ISPs provide /64 per household. Ugh.

Seriously? They assign internal addresses (10/8, 172.16/12, 192.168/16) to all customers?

Are you able to name the ISP?

ISPs usually use the designated block (100.64.0.0/10) for this to avoid collisions with home networks: https://tools.ietf.org/html/rfc6598#section-7

Webpass is an example of a "good" ISP that does this. It's my only qualm with them. Besides that they are outstanding. IPv6 works great.

That's fairly normal these days. The combination of ipv6 + cgnat for ipv4 (carried over the v6) is called DS-Lite[0]. ISPs in asian countries have been doing that for years now european and american ISPs have been ramping it up recently too.

[0] https://tools.ietf.org/html/rfc6333

ISPs in asian countries have been doing that for years

And they usually call it "web access" or something similar, never speaking of an "Internet connection". Which is what it is, a way to access websites and usually not much else.

Is it really? Apart from the missing port-forwarding, DS-Lite seems to be one of the better solutions to the IPv4 shortage to me. There's only a single NAT at the ISP, the local router tunnels IPv4 packages directly to the AFTR. For peer-to-peer applications, both UDP and TCP hole punching work fine.

Maybe some ISPs will implement the Port Control Protocol [1] at some point, which would allow port forwarding with the DS-Lite NATs.

[1]: https://tools.ietf.org/html/rfc6887

> For peer-to-peer applications, both UDP and TCP hole punching work fine.

Sadly, that's only half correct. Yes, nat traversal usually works to establish connections. But in practice port mappings are not necessarily the same thing as NAT table entries. If your p2p application contacts a lot of endpoints, even from the same source port, this can eventually lead to saturation. At that point you'll get packet drops and ICMP errors.

In other words, on some aftr implementations p2p can lead to resource exhaustion, leading to a pretty bad ipv4 experience.

> Maybe some ISPs will implement the Port Control Protocol [1] at some point, which would allow port forwarding with the DS-Lite NATs.

Some already do. The CPE can forward local mappings to the AFTR.

I think we need a mandate for ISPs to make it clear when the product they're offering is not internet connection.

ISP's in India have started using this method. I am currently using such an ISP.

Is it rare?

I think BT's cheaper broadbands do this, for one.

I certainly have never encountered this, and would be really unhappy if my ISP pulled this stunt.

Only the early players get the luxury of large IP pools, everyone else has had to resort to carrier-grade NAT.

Fortunately some of those can un-NAT you if you ask politely.

BT does this unless you either have an Unlimited package or opt out through their website.

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