I spent a week without IPv4 (2023)

https://www.apalrd.net/posts/2023/network_ipv6/

by mahirsaid • 7 months ago

168 360 7 months ago

glitchc• 7 months ago

While these articles are useful in understanding the utility of IPv6, what would really help is an article explaining step by step how to configure a home network using IPv6. The tutorial should answer these questions:

- How to ensure there are no collisions in address space? Translates to, how to pick safe addresses, is there a system?

- How do I route from an external network resource to an internal network resource? Translates to, can you provide syntax on how to connect to an smb share? Set up a web service that works without WireGuard or equivalent?

- How does one segment networks, configure a vlan, set up a firewall?

candiddevmike6• 7 months ago

- if you're talking a private/local prefix, you can use tools like this to generate one: https://unique-local-ipv6.com/. Otherwise DHCPv6 and SLAAC will ensure no collisions for the most part.

- Use global/public addresses on all your devices (using something like prefix delegation) or use NAT.

- Same as IPv4. Prefix delegation will let your ISP assign you multiple networks, and then most routers will break these up into /64 networks for each of your VLANs.

Latty2• 7 months ago

- SLAAC - the address spaces for IPv6 are so huge, collisions are extremely unlikely outside of intentional actions.

- Open holes through firewalls, point DNS at the address, and it should just work, the joys of actually having public addresses.

- Same way as with IPv4 mostly. The only real difference is because SLAAC assumes a /64 you probably want your networks to be at least that big.

oezi• 7 months ago

extremely unlikely outside of intentional actions.

But come on! It is a legitimate question, do you just scramble keys when picking an address?

the joys of actually having public addresses.

If your ISP gives you a static IPv6. Unfortunately in Germany none of the ISP for private users does (last I checked).

jcgl7• 7 months ago

- Devices using SLAAC (idk about DHCPv6) do a thing called Duplicate Address Detection to manage just this. No need to worry. If you’re manually assigning addresses and have a conflict, one of the devices will mark its address(es) as duplicate and refuse to use them. Quite useful.

- Easiest is to use your devices’ public (“global unicast”) addresses and allow traffic on your firewall. This is how IP was meant to be used; no NAPT in sight. If you like, you can use ULAs locally and then do NPTv6 for internet-facing access. But I’d recommend against that to start.

Regarding the services, there’s not really anything IPv6 specific. Whether v4 or v6, you shouldn’t be exposing SMB to the internet. Whether v4 or v6, you can put any IP-based service behind Wireguard or any other tunneling solution. There’s nothing specific to v6 there; just use v6 addresses in your config, and you’ll be good to go.

- Basically the same way as with v4; IP (whether v4 or v6) have mostly the same semantics in their layer (layer 3). The only thing is that you’ll want to allow certain kinds of ICMPv6 traffic, assuming your firewall vendor doesn’t do that out of the box. When it comes to VLANs, that’s layer 2, so your layer 3 protocol doesn’t play any role there.

Network segmentation is way more fun with v6 because you have enough address space to make nice hierarchical topologies.

candiddevmike6• 7 months ago

I wish I could switch my network to all IPv6 and use NAT64/DNS64, but Android, the world's most popular OS, purposefully disables DHCPv6. I am forced to support IPv4/DHCPv4 for the foreseeable future to support these broken devices.

avidiax4• 7 months ago

Why can't you use stateless autoconfig?

candiddevmike6• 7 months ago

Because I want to control the suffix assigned to devices for firewall rules and monitoring purposes.

franklyworks2• 7 months ago

Android supports SLAAC and has good support transitional tech like xlat464 and DHCP option 108.

I have used these on my network and office to move to IPv6-only for Android.

What about lack of DHCPv6 prevents you from using IPv6 on Android?

candiddevmike6• 7 months ago

I can't run SLAAC and DHCPv6 at the same time without giving devices multiple addresses, and Android doesn't support DHCPv6, so I'd have to carve out a separate, SLAAC-based, android-only network. And then figure out firewall rules, multicast reflection, etc.

dmm• 7 months ago

Android supports DHCPv6, just not stateful DHCPv6. You can give each device its own /64 or if you really want to track a devices usage you should use an authenticated layer on top of your base network.

throw0101c13• 7 months ago

I wish I could switch my network to all IPv6 and use NAT64/DNS64, but Android, the world's most popular OS, purposefully disables DHCPv6.

It does not "disable" DHCPv6. It does not support DHCPv6. Android (really Lorenzo Colitti) in/famously WONTFIX adding DHCPv6 client support:

* https://issuetracker.google.com/issues/36949085

Of course after over a decade of denying that Android needs some kind of DHCP in IPv6, it seems that Android may finally be getting some kind of solution:

* https://android-developers.googleblog.com/2025/09/simplifyin...

* Via: https://blog.ipspace.net/2025/09/android-dhcpv6-prefix-deleg...

Hopefully, having admitted (?) the error of their ways with being SLAAC-only they'll also add 'regular' DHCPv6 in addition to DHCPv6-PD.

denkmoon• 7 months ago

Holy hell the android dhcpv6 situation is deranged. Been following Mr Colitti’s antics for awhile but only just learned of this prefix delegation news. So now I can delegate an entire subnet but can’t just have a regular address. Why oh why can’t we just have a goddamn normal every day dhcpv6 client like every other os on the planet

avidiax4• 7 months ago

People keep saying that IPv6 allows you to more easily host services, but you still have to support IPv4.

Try connecting to your IPv6-only service on Hotel WiFi -- you usually can't.

It's unfortunate, but IPv6 doesn't really solve any problems for a home user. And I say this as someone that has deployed IPv6 at home before.

mattypg2• 7 months ago

It's unfortunate, but IPv6 doesn't really solve any problems for a home user.

CG-NAT and strict NAT in general. Newer ISPs often force users onto CG-NAT, and my consoles have had numerous issues with NAT in general over the years. ISP routers also often make fixing this an opaque or impossible problem for the user.

I don’t think IPv6 is the best thing ever, but I do think it solves the problems IPv4 did along with some annoying issues IPv4 struggled with.

brandonkal• 7 months ago

It does make it easier. IPv6 pinholes are simpler than port forwarding. My IPv4 is not static but my IPv6 prefix is. So I don’t need dynamic DNS. I have no IPv4 port forwards, instead I run snid on a VPS to support legacy internet clients and call it a day.

avidiax4• 7 months ago

https://github.com/AGWA/snid

So you basically have a cloud server and a domain with a wildcard record, and you then forward IPv4 through IPv6?

I think this somewhat proves my point that IPv6 doesn't solve much for self-hosting. You still need some kind of working IPv4 setup. You are using IPv6 in place of either a reverse proxy or something like tailscale, which I suppose is more convenient.

jrm42• 7 months ago

Hot take: IPv4 might be techinically worse, but it's "politically" (in the classic sense of the word) better.

IPv6 essentially enables "universal internet IDs" for every device, which could streamline a lot of things, but enable a lot of weird surveillance/power balance issues that the cruft of IPv4 is actually incidentally helping guard against.

Again, I'm old enough to remember when e.g. the ISPs were going to try to charge per device in each household.

blahaj2• 7 months ago

Again, I'm old enough to remember when e.g. the ISPs were going to try to charge per device in each household.

I don't really see that coming again and if it does you can just do NAT66 just like you can do NAT4.

jrm42• 7 months ago

You and I can, yes.

But, network effects.

ninkendo5• 7 months ago

This hasn’t been the case in decades, every OS defaults to randomly generating the trailing 64 bits of your address and cycling through new addresses periodically. Your IPv6 address is only fixed to your device if you choose to configure it that way.

Since the network half (leading 64 bits) is as fixed as your IPv4 address was, and the host half is random and constantly changing, an IPv6 address is exactly as uniquely identifying as an IPv4 address used to be.

nebalee• 7 months ago

Afaik, at least Fedora has the privacy extensions disabled by default.

mojuba• 7 months ago

Groups of zeros can be omitted with two colons, but only once in an address (i.e. 2000:1::1, but not 2000::1::1 as that is ambiguous)

Can someone explain why it's ambiguous?

On the subject, IPv6 is one of the strangest inventions on the internet. Its utility and practically are obvious no matter how you look at it except... just one thing.

Network-related things are generally easy to remember and then type from memory: IPv4, domain names, standard port numbers. Back in the day it was the phone numbers, again, easy to remember and dial when you need it. IPv6 is just too long and requires copy/paste all the time. This is the only real reason in my opinion, why IPv6 is doomed to be second-grade citizen for (probably) a few more decades.

boob• 7 months ago

Can someone explain why it's ambiguous?

Because you don’t know how many zeroes are on each side around the 0001 in the middle.

It can be 2000:0000:1:0000:0000:0000:0000:1 or 2000:0000:0000:0000:0000:1:0000:1 etc.

koakuma-chan2• 7 months ago

This shortcut system of ipv6 only makes it worse. It's too hard to remember how it works.

ggm2• 7 months ago

whats the rule to say where the first 1 floats between the 2000: and the :1 at the end? the :: rule says "all zeros" but not how long.

doubletwoyou• 7 months ago

the :1 is short for :0001 basically and then just put that bit of the address at the very end and put the first bit of the address at the front, and then just fill each missing group inbetween with 0000

db48x10• 7 months ago

It’s a really complicated rule called “subtraction”. Addresses are always 128 bits long, or 8 groups of four hex digits. 2000::1 is two groups, so you need six groups in between to make 2000:0000:0000:0000:0000:0000:0000:1. But I don’t know why people always ask this, because it’s always the computer you are typing addresses in to that does the subtraction. You never ever have to type out the whole address. Just type the shortened version, because 2000::1 _is_ the whole address.

ggm2• 7 months ago

My answer was too terse. IF there was two :: in the address, then the length of EACH :: denoted section is not known. It can be either longest left :: or longest right :: and that wasn't defined, because the rule is THERE IS ONLY ONE :: section.

Posed as a question, disingenuously.

clashandcarry• 7 months ago

2000:1::1 would expand to 2000:0001:0000:0000:0000:0000:0000:0001

2000::1::1 could be 2000:0000:0000:0000:0001:0000:0000:001, or 2000:00000000:0001:0000:0000:0000:001

There's ambiguity on where to fill in the five groups of 0000 in the second case.

rockskon• 7 months ago

The second address is invalid. You can only use :: once per address.

Edit: Whoops. Didn't read what the above post was in response to. My bad.

nwellinghoff• 7 months ago

I said this in a previous post and was shot down hard. I think you are right. Every time I look at a ipv6 address my brain goes “fack this”.

WarOnPrivacy6• 7 months ago

Every time I look at a [long] ipv6 address my brain goes “fack this”.

I do get that but I also get 'There are so many I could have all I wanted ... or I could if any of our fiber ISPs would support it, that is'

mike_d3• 7 months ago

IPv4 isn't perfect, but it was designed to solve a specific set of problems.

IPv6 was designed by political process. Go around the room to each engineer and solve for their pet peeve to in turn rally enough support to move the proposal forward. As a bunch of computer people realized how hard politics were they swore never to do it again and made the address size so laughably large that it was "solved" once and for all.

I firmly believe that if they had adopted any other strategy where addresses could be meaningfully understood and worked with by the least skilled network operators, we would have had "IPv6" adoption 10 years ago.

My personal preference would have been to open up class E space (240-255.*) and claw back the 6 /8s Amazon is hoarding, be smarter about allocations going forward, and make fees logarithmic based on the number of addresses you hold.

WarOnPrivacy6• 7 months ago

Network-related things are generally easy to .. type from memory [but] IPv6 is just too long

I was reminded of this 2d ago; I was testing one IPv6 WAN from another. DDNS had failed so I didn't have my usual crutch to lean on.

ekropotin4• 7 months ago

I mean yes, but there’s no escape from the fact that ip addresses need to be longer as amount of devices on the internet already exhausted the pool of IPv4 addresses by multiple orders of magnitude.

I guess it could be possible to implement sort of mnemonic phrases for addresses, à la bip-39, but it would be just trading one kind of pain for another.

api4• 7 months ago

I've said this since time immemorial, and networking people often dismiss it. "Just use DNS," say people who have never actually worked netops or devops.

The length of the addresses and the clunky nature of their ASCII representation is absolutely the #1 reason the IPv6 has taken this long. User experience is the most powerful force affecting large scale adoption, and IPv6 has poor UX.

I think the UX is partly fixable by creating less horrible ASCII representation, but this would take a lot of coordination that was hard even back then and is virtually impossible now. If someone told me in 500 years we're still running dual-stack IPv4/IPv6 absolutely unchanged, I'd believe it.

zamadatix2• 7 months ago

Half the reason (literally) the address looks so bad is not because of IPv6 but because everyone keeps choosing to implement randomized in-subnet addresses and cycle through them for privacy reasons.

E.g. 2600:15a3:7020:4c51::52/64 is not too horrible but 2600:15a3:7020:4c51:3268:b4c4:dd7b:789/64 is a monster by unrelated intent of the client.

throw0101c13• 7 months ago

This is the only real reason in my opinion, why IPv6 is doomed to be second-grade citizen for (probably) a few more decades.

Except if you're using a mobile phone, in which case many telcos hand out only IPv6 addresses to handsets. 2018 NANOG presentation "T-Mobile's journey to IPv6":

* https://www.youtube.com/watch?v=d6oBCYHzrTA

From 2014, "Case Study: T-Mobile US Goes IPv6-only Using 464XLAT":

* https://www.internetsociety.org/deploy360/2014/case-study-t-...

But who cares about mobile phones, right? They're only second-grade devices.

ck2• 7 months ago

my tmobile 5g modem has ipv4 but changes ip every single page load, it's wild

I'm used to cablemodems with static ipv4 for months basically until mac changes

zajio1am3• 7 months ago

IPv6 is just too long and requires copy/paste all the time.

That is only true for autogenerated/SLAAC IPs. In contrast, manually assigned IPs are often much simpler and easier to remember in IPv6 than in IPv4. I have one common subnet prefix that can be uniformly split to end networks and last number in IP address for such network always end with 0 (and therefore the first device is xxx::1). While in IPv4 i had multiple prefixes, each split non-uniformly based on how many devices was expected to be on that end network, and because most end network prefixes were smaller than /24 (say /26-28), the last number of IP address varies between these networks.

mlangenberg3• 7 months ago

There are also still a lot of misconceptions from network administrators who are scared of or don’t properly understand IPv6

Enable IPv6 on a TP-Link Omada router (ER7212PC) and all internal services are exposed to the outside world as there is no default IPv6 deny-all rule and no IPv6 firewall. I get why some people are nervous.

gz09• 7 months ago

I believe that was more a bug in the firmware that's been fixed for a while now.

buggjenrmf5• 7 months ago

A bug that was implemented, because ipv6 is more complex to secure.

mlangenberg3• 7 months ago

In case of the ER7212PC, it’s only fixed in the v2 hardware revision.

No free upgrade.

throw0101c13• 7 months ago

Enable IPv6 on a TP-Link Omada router (ER7212PC) and all internal services are exposed to the outside world as there is no default IPv6 deny-all rule and no IPv6 firewall. I get why some people are nervous.

A router routing traffic makes people nervous? Isn't that what it's supposed to do? I'd be annoyed if my router did not pass traffic.

Now, if the ER7212PC was a firewall that would be something else.

(And no, I'm not being pedantic: routers should pass traffic unless told otherwise, firewalls should block traffic unless told otherwise. The purposes of the two device classes are different, they just happen to both deal with Layer 3 protocol data units.)

tsimionescu4• 7 months ago

Are you suggesting that people should buy both a router and a firewall for their home networks? I suppose they should buy a separate Wi-Fi AP as well, and a switch or two, in your opinion?

baobun• 7 months ago

Routers and access points are also typically separate device classes. Yet the market has figured out that most consumers prefer all-in-one devices. Expecting households to run dedicated firewalls besides their AiO wifi-routers is ludicrous.

What firewall do you recommend a typical user couple their ER7212PC (which BTW is already tripling as VPN gateway and cloud-controller) with?

The problem is that TP-link does not give two cents to security in their products.

And no, I'm not being pedantic

You very much are.

flumpcakes5• 7 months ago

You are of course correct, but most people will disagree because the world we live in is a lot messier than what we should do and people expect a base line. You have to remember that people rely on IPv4 NATing for security, despite every network engineer knowing that is it is not - in effect it is.

zajio1am3• 7 months ago

'firewall' is just a colloquial term for packet filtering, which is a term for a class of functionality that could be provided by a router.

Customer edge routers are expected to contain firewall (see RFC 7084 and RFC 6092).

shrx2• 7 months ago

People expect their router to act as a firewall too, via NAT. If you take this away and force people to buy an additional piece of hardware to restore the expected functionality, they won't switch. Simple as that.

jeroenhd4• 7 months ago

That's more proof that TP-Link should not be trusted than that there is a problem with IPv6, really. Even cheap $20 Aliexpress routers have a firewall enabled by default.

mlangenberg3• 7 months ago

Agreed.

jyscao• 7 months ago

I need to switch my home network to at least use IPv6 externally, because my ISP recently deployed CG-NAT, which made my SSH server that used to work no longer reachable from outside of my LAN.

bakugo• 7 months ago

You can use a NAT-traversing VPN like tailscale to work around this.

karlshea7• 7 months ago

My two IPv6 issues (even having had a HE tunnel in the past):

- My local ISP (US Internet, soon to be part of T-Mobile Fiber) hasn't enabled it, even though the CEO has said on Reddit for years that it's a priority. Now that they've been acquired who knows if it'll ever happen.

- Linode allows transferring v4 addresses between machines, so if I need to rebuild something I can do so without involving my client who usually has control over DNS. They do not support moving v6 addresses, which means that the only sites I have control over that support v6 are the ones that I control DNS.

Making IPv6 a thing seems like it would be super easy if a couple hours could be spent solving a bunch of dumb lazy problems.

toast03• 7 months ago

My local ISP (US Internet, soon to be part of T-Mobile Fiber) hasn't enabled it, even though the CEO has said on Reddit for years that it's a priority. Now that they've been acquired who knows if it'll ever happen.

Being a priority doesn't mean it's high priority. It could be a priority, but the lowest ranked one, so other stuff always comes first. :P

T-Mobile wireless US is pretty invested on IPv6, so if they take over the network, they may well push it.

karlshea7• 7 months ago

It "finally hit the top of the project list" two years ago so we'll see lol.

It's "T-Mobile Fiber Home Internet" which looks to be a bunch of local ISPs they've been snatching up, so we'll see what happens. USI's customer service and reliability have been amazing so hopefully that doesn't get screwed up.

rao-v5• 7 months ago

What’s the pragmatic solution to ipv6 allowing everybody in my household to be trivially and stably mapped to a unique subnet? I like the accidental semi-randomization that ipv4 and ISP NAT offered and I don’t see anything like it short of putting my entire home net on a VPN (it’s expensive and can’t keep up with my ISP’s bandwidth)

yjftsjthsd-h5• 7 months ago

It's true that you won't get CGNAT without having CGNAT. Depending on your concern, it is possible to NAT66 to make your entire network appear as one IP.

rao-v5• 7 months ago

I’d love to pay my ISP to rotate my ipv6 subnet every week. It’s not an option. My comcast IP changes every so often and that’s of some value.

It’s very unclear to me why people should be able to deterministic reach out to a specific device on my network. It has no value to me unless I run a service.

lloeki• 7 months ago

Each device gets directly addressable from WAN with v6 but it also gets a randomised privacy IP that rotates very frequently so each individual device is just as "hidden" as it was with v4+NAT.

Your v6 subnet prefix is no different than whatever WAN-side v4 your NAT had. "Accidental semi-randomization" of the WAN side IP is not something one could reliably count on. Many ISPs just hand over a static-like IP, that is, even when it's supposed to be random the pool of IPs is so constrained that it's usually the same simply through the IP lease surviving power cycling. And that was before CGNAT.

If your concern is being identifiable through your IP then counting on whatever v4 artifact is the wrong move. Use a VPN with randomised exit nodes.

rao-v5• 7 months ago

I don’t know of a ISP that will randomize in anyway your v6. It’s tied to your account forever.

It’s of some practical real world value that people cannot resolve v4 IPs to individual households with certainty. It’s a shame to lose that value.

mattypg2• 7 months ago

It’s a little different, but you can use ULAs to have a static subnet with static device addresses.

One of the biggest changes from IPv4 when I enabled IPv6 a while back was that it’s fine and normal to have multiple addresses per interface now. ULAs are not globally routable, so I think of them as LAN addresses. Another option that comes to mind is mDNS, but I think support for that is not as widely accepted.

Global addresses can change, just as your home dynamic IPv4 probably did from time to time.

icedchai3• 7 months ago

Everybody in your household is already mapped to a single IPv4 address that rarely changes with most ISPs. Mine hasn't changed in over 3 years. My IPv6 /56 prefix delegation hasn't changed, either.

lonjil• 7 months ago

what exactly do you mean by "trivially and stably mapped to a unique subnet"?

jcgl7• 7 months ago

ULAs. It’s like a better version of v4’s RFC1918 addresses.

rao-v5• 7 months ago

ULAs don't keep you from every internet connection from your household being trivially linked to your GUA.

tlogan• 7 months ago

As a normal user: why do I need IPv6?

As far as I know, the majority of websites (about 70%) do not support IPv6.

badgersnake• 7 months ago

I don’t think that’s true. But of course it depends how you’re measure the majority of websites.

Most of the figures I see show 60-70% of the top 100 sites do support it. But maybe that does not reflect your usage.

Why do you need it? Maybe you don’t right now since ipv6 only sites are niche. The most tangible advantage I’ve seen is avoiding CGNAT. Gamers in particular don’t like that because it introduces latency. Services like Xbox live definitely do support ipv6 for this reason.

paulddraper7• 7 months ago

You need it because there aren’t enough IPv4.

If you have a mobile device with data, you’re likely already using it.

sethops1• 7 months ago

Do we really need all the mobile phones and IoT devices of the world to be publicly addressable? Is that even a good thing?

jeroenhd4• 7 months ago

Depends on your ISP. If you live in a place where there aren't many IPv4 addresses available, CGNAT is the reason you're seeing a lot of Cloudflare/Akamai/Google CAPTCHAs everywhere, and IPv6 fixes that.

calvinmorrison• 7 months ago

same reasons northern europeans had to invent all sorts of fancy food preservation and complex power struggle societies revolving around crop limitations and war.

Meanwhile closer to the equator, much less progress was needed to live and let live.

In short, Americans are native tribes. we have plentiful IPV4 and couldnt care less about SLAAC or whatever other complex moon sun and seasonal tide gods, salted codfish and salt mining operations. we just dont need to care about long addresses, they're plentiful here.

Animats• 7 months ago

Here's China's current IPv6 plan.[1] It was an explicit objective of the 14th Five Year Plan, now concluding, to get most of China's Internet on IPv6. About 70% of China's mobile users are on IPv6 now. But fixed IPv6 traffic in China is only 27%.

[1] https://www.cac.gov.cn/2025-05/20/c_1749446498560205.htm

orangeboats5• 7 months ago

Their IPv6 deployment rate saw a huge jump from 40ish% to 53% after this report though.

https://stats.labs.apnic.net/ipv6/CN

PaulKeeble• 7 months ago

When I moved to an ISP that supported IPv6 earlier this year I ran into niggly problems. Ubuntu failed to update because one of its regional servers was misconfigured. OpenDNS one of its servers seemed not to be there on a regular basis over IPv6. I also had odd behaviour and latency issues where sometimes IPv6 would fail to route for short periods and it would fail and fall back to IPv4.

It was a painful experience of trying to work out if I had misconfigured it, if it was something to do with my opensource router software or if it was my ISP or the end services. I didn't get to the end of working this out and reporting issues and I just gave up. Due to the intermittent nature of the issues I was facing I never managed to get a report of issues my ISP would accept.

So I'll give it some time and give it a try after a year and see if things have improved, but it was definitely not ready for prime time.

layer8• 7 months ago

If Google would announce that Chrome is dropping IPv4 support in n months, that would probably get things moving. ;)

stevekemp• 7 months ago

I guess it would, but remember there are more services out there than just HTTP(S).

For example the last time I had an IPv6-only host I had issues cloning things from github, as "git clone git@github.com..." failed due to github.com not having IPv6 records.

A quick search revealed this open 3+ year old discussion - https://github.com/orgs/community/discussions/10539

buggjenrmf5• 7 months ago

You’re in luck, github is in the process of moving to azure!

Dagger210• 7 months ago

A quick workaround for that is to use one of the DNS servers from https://nat64.net/. There are also people running reverse proxies specifically for GitHub, e.g. https://danwin1210.de/github-ipv6-proxy.php.

(Ideally your ISP would be running NAT64 for you, especially if it's a VPS provider only giving you v6, but for whatever reason few of them do...)

lostmsu• 7 months ago

Would have to be ChatGPT these days.

idatum2• 7 months ago

OpenBSD makes it easy to try IPv6 tunnelbroker.net with NAT64/DNS64 if your ISP only has IPv4 ("one more lab test away.." they say).

This has worked for me well for a couple years. I do use a VLAN to keep the IPv6-only network separate (homelab) from video streamers in the household.

In my pf.conf:

    # IPv6 tunnel
    block in log on $tun6_if all
    block in quick on $tun6_if inet6 from fd00::/8 to any
    antispoof quick for $tun6_if
    # allowed icmp6
    pass in quick log on $tun6_if inet6 proto icmp6 icmp6-type {
        unreach, toobig, timex, paramprob, echoreq
    }
    # MSS clamping 60 bytes less than HE 1480
    # 20 byte IPv4 tcp header + 40 byte IPv6 ip header
    match on $tun6_if all scrub (random-id max-mss 1420)

and in /var/unbound/etc/unbound.conf:

    # DNS64/NAT64
    module-config: "dns64 validator iterator"
    dns64-prefix: 64:ff9b::/96

Done. I don't have 464XLAT on Win11 but I do want to know if there's a hard coded IPv4 address anyway. I never had an issue.

idatum2• 7 months ago

Forgot the most important part of pf.conf!

    # NAT64
    pass in inet6 from any to $nat64_prefix af-to inet from ($ext_if)

jrmg• 7 months ago

I’m surprised home many technically knowledgeable people on Internet forums still think IPv6 is some niche, unreliable thing.

In my direct experience, in the USA, at least Spectrum, AT&T, and Xfinity (Comcast) still run IPv4, of course, but they also have IPv6 working and on by default on their home internet offerings.

All mainstream computer and mobile OSes support it by default and will prefer to connect with it over IPv4.

‘Everyone’ in many areas is using it. For many of us, our parents are using Facebook and watching Netflix over it. Over 50% of Google’s American traffic is over it. It just works.

phito• 7 months ago

Myeah... I've had weird issues on my network that I could only resolve by disabling IPv6. Granted, it's probably my fault, but if everything still works fine with ipv4 that's fine to me. One day I will get into it and learn how it work and maybe I'll get it figured out... One day...

Dagger210• 7 months ago

Random guess: PMTUD? Like on v4, some people fuck up their PMTUD and are incapable of realizing or fixing it, so you have to have some kind of workaround.

If setting your client machine MTU to 1280 (`ip link set mtu 1280 dev eth0` or equivalent) magically fixes it, that's your problem.

opan• 7 months ago

I had working IPv6 in the past, but currently I seem to have no working IPv6. Using Xfinity. I have access to some servers at a friend's place in another city, pretty sure he also doesn't have IPv6. Maybe some phone calls would sort it out, but when "everything" still works (with IPv4), it's hard to care.

bigstrat20032• 7 months ago

That is really bizarre, because I have Comcast and I find their IPv6 support excellent. The only complaints I have are that I wish you could get bigger than a /60 prefix (a /56 would be nice), and that I wish it was feasible to get a static prefix as a residential customer. Granted you said you don't really care to fix it, but if that ever changes I do think you could get them to fix it pretty easily. IPv6 is one of the things they generally do right.

paulddraper7• 7 months ago

It just works.

Until you want to like, use GitHub.

notKilgoreTrout2• 7 months ago

There is a clean bifurcation between just works and Microsoft compatible.

LeoPanthera• 7 months ago

My problem with IPv6 is that my ISP (Xfinity) won't give me a static prefix, so every now and again it changes.

Unlike IPv4, my LAN addresses include the prefix, so every time they change it, all my LAN addresses change.

Combined with the lack of DHCP6 support in many devices, this means reverse DNS lookups from IP to hostname can't be done, making identifying devices by their IP essentially impossible.

hdgvhicv3• 7 months ago

My ISP will route as many /64s to me as I want (I think I get a /48 by default, I guess if I want more than 64k subnets I’d have to justify it)

So I don’t have the changing ip issue. I do however have an issue if I want to change ISP as it’s a whole mess of rules to update rather than a couple of dns entries and two dst nat rule (one per public IP)

I believe the idea in v6 if you have multiple prefixes on the same network - including a local fc00::/7 one for local services. Layers and layers of things to break.

baq• 7 months ago

you should advertise a local prefix (anything in fd00::/8) in your network and it should just work. no need to use the isp-provided prefix for lan.

db48x10• 7 months ago

I think you’re conflating multiple things there. There’s nothing magical about IPv4 that gives your LAN addresses stability when your ISP changes your IP prefix. That’s provided by your router doing network address translation. You send a packet from your address which is 192.168.0.42 (a local address), and your router changes the bytes in the packet so that it comes from X.Y.Z.W (your router’s public address). If you really wanted it to your router could do the same thing for IPv6.

IPv6 also has local addresses, but a lot more of them. Anything starting with fd00::/8 is a local address with 40 bits available as the network number. So you can set up your local network with the prefix fdXX:XXXX:XXXX::/48 (where the Xs are chosen randomly) as the prefix and still have 16 bits left over for different subnets if you want. These addresses do not change when your ISP changes your public prefix.

And if you want to add reverse dns for SLAAC addresses then just have your router listen for ICMPv6 Neighbor Announcement addresses and use them to update your DNS server as appropriate. Or configure your servers to use stable addresses based on their MAC address rather than random addresses (which are better for privacy), and then just configure the DNS as you add and remove servers.

bcoates• 7 months ago

Is reverse dns even a thing outside of irc and forgetting to give command line tools the "don’t be slow" flag?

karlshea7• 7 months ago

Use a ULA (unique local address) for everything internal that you want shorter. It's just like rfc1918 addresses except you don't need NAT.

Sleaker• 7 months ago

Well.. that's because with ipv6 you're not technically on a lan everything is exposed by default unless you set it all up differently.

throw0101c13• 7 months ago

Unlike IPv4, my LAN addresses include the prefix, so every time they change it, all my LAN addresses change.

Yes, a topic of active discussion at the IETF. See perhaps BCP RFC 9096, "Improving the Reaction of Customer Edge Routers to IPv6 Renumbering Events":

* https://datatracker.ietf.org/doc/html/rfc9096

And informational RFC 8978, "Reaction of IPv6 Stateless Address Autoconfiguration (SLAAC) to Flash-Renumbering Events":

* https://datatracker.ietf.org/doc/html/rfc8978

A few drafts, like "Improving the Robustness of Stateless Address Autoconfiguration (SLAAC) to Flash Renumbering Events":

* https://datatracker.ietf.org/doc/html/draft-ietf-6man-slaac-...

Using ULA seems to be what a lot of folks recommend:

* https://en.wikipedia.org/wiki/Unique_local_address

hdgvhicv3• 7 months ago

Corporate laptop won’t work (their version of windows seems to require an ipv4 adddess on an interface, not sure if that’s a windows thing or a them thing)

Doesn’t remove the need for nat - my wired IsP might be able to bgp with me, but my backup 5g won’t, and when I want to choose which to send my traffic through with PBR that means natting.

My router doesn’t support 64, so I have to use my isp’s which is speed constrained compared with native 4. Ok that’s on my setup. Haven’t tested my 5g provider and where 64 occurs, I’d hope in their network, but how do I configure my dns64.

Still need to provide v4 at the edge and thus 46 nat so I can reach internal v6 only servers from v4 only locations

Perhaps lost of that is because my router doesn’t do 64, but again that just shows that v4 is still essential. I haven’t found a single service that’s v6 only, so if I have to run a v4 network (even if only as far as a 64 natting device) why bother running two networks, double the opportunity for misconfiguration and thus security holes. Enabling dual v6 on my IoShit network would allow more escape routes for bad traffic, meaning another set of firewall rules to manage. Things like SLACC make it harder to work out what devices are on the network, many end user devices are user hostile now and keeping control of them on v4 alone is less work than in v4 and v6.

labcomputer• 7 months ago

Doesn’t remove the need for nat - my wired IsP might be able to bgp with me, but my backup 5g won’t, and when I want to choose which to send my traffic through with PBR that means natting.

Yes, it does. You just have each of your routers (wired and 5G) advertise the /64 prefix delegated by each of your ISPs. Your hosts will self-assign a v6 address from each prefix.

To control which link the traffic uses, you just assign router priority in the router advertisement (these are all standard settings in radvd.conf).

Things like SLACC make it harder to work out what devices are on the network

Again, not true. If you really don’t trust your devices, then DHCP isn’t going to save you. Malicious hosts absolutely can self assign an unused v4 address, and you’ll be none the wiser if you just look at your DHCP leases.

bblb• 7 months ago

their version of windows seems to require an ipv4 adddess on an interface

Could be DirectAccess. Microsoft's earlier built-in VPN solution before Always On VPN. DirectAccess works only with IPv4 inbound so you can't use IPv6 only stack. Under the hood it uses a combination of v4-v6 transition and translation protocols, but it still requires the Windows client machines to have IPv4 addresses.

If you can run PowerShell commands on the laptop and if "Get-DnsClientNrptPolicy" returns some DirectAccessDnsServers then it's DA laptop.

mightyham6• 7 months ago

For consumer traffic, your probably right. In data centers, cloud computing, and various enterprise networking solutions, IPv4 is still king. I'm sure IPv6 would work fine in all these use cases, but as long as many large tech companies are not exhausting the CIDR ranges they own (or can opt for using private ranges) there is no impetus to rework existing network infrastructure.

betaby• 7 months ago

cloud computing

Nope. Large scale DCs are IPv6 only underneath, exascalers like Google and Meta have stated that multiple times. I.e. https://www.youtube.com/watch?v=Q3ird3UDnOA also see various NANOG talks https://www.youtube.com/@TeamNANOG/videos

ekr____2• 7 months ago

Well, for some value of "just works".

For example, I recently attended the IETF meeting in Montreal, which offers a by default v6-only network. My Mac worked fine, but my son's school-issued Chromebook had glitchy behavior until I switched to the network that provided v4.

josephg2• 7 months ago

Sounds like exactly the sort of thing the IETF's IPv6-only network is trying to shake out.

I went to IETF a few years ago and ran into issues on their IPv6 only network because I host some stuff from home, and my residential ISP doesn't support IPv6 at all. It made me really want to get all that fixed.

ekr____2• 7 months ago

Well, for some value of "just works".

For example, I recently attended the IETF meeting in Montreal--practically the epicenter of v6 thinking--which offers a by default v6-only network. My Mac worked fine, but my son's school-issued Chromebook had glitchy behavior until I switched to the network that provided v4.

cornonthecobra2• 7 months ago

CenturyLink, an ILEC, only offers IPv6 using 6rd gateways. The IPv6 throughput is a fraction of IPv4 and has much higher latency. During peak times, the 6rd gateway saturates, forcing me to stop advertising the prefix to restore internet access. It has been this way for years.

It is also impossible to report IPv6-specific outages. CenturyLink technical support is the worst of the worst, with agents utterly incapable of doing more than pushing a "check ONT" button on their end and scheduling a technician visit with a multiday window. If you ask them for the 6rd configuration information, they act like you're speaking an alien language.

Even among their technicians, IPv6 knowledge is rare. Imagine the guy installing hundreds of dollars of gigabit fibre equipment at your demarc staring you like an idiot because you spoke two extra syllables between "IP" and "address". I'd think the term "IPv6" is chatbot poison if it weren't for the fact it's a human physically in front of me.

The result is their service is effectively IPv4-only.

toast03• 7 months ago

I had CenturyLink CPE that would crash when a fragmented IPv6 transitted it. That was fun :P. They're also all in on PPPoE and at least on my VDSL2 line, didn't enable RFC 4638 (baby jumbos) to get back to MTU 1500. Pretty happy to be on muni fiber now (although the installation cost was huge).

kstrauser5• 7 months ago

Ah, good ol’ CenturyLink: “We put the TTY in TTY.” Be happy it’s not IPv4 over telegraph.

6r17• 7 months ago

I'm "niche" - but i had issues with Wireguard being able to connect me through ipv6 to a v4 - other than that i spent most of my time on v6 and as you said it just works

esseph2• 7 months ago

Yes the largest companies have the most resources. Makes sense.

Most do not.

There are far more single person, small, and mid sized companies that do not.

This includes b2b, regional ISPs, etc.

nine_k2• 7 months ago

T-Mobile, a major phone provider, runs an ISP which is IPv6 only. That is, your phone never gets an IPv4, unless connected to WiFi. They offer home access points with a 5G modem and a router; the external address is also IPv6 only.

It works plenty well. I access everything accessible via IPv6, and the rest through their 464XLAT, transparently.

My LAN still has IPv4, because some ancient network printers don't know IPv6. OpenWRT on my router supports IPv6 just fine. Of course I do not expose any of my home devices to the public internet, except via Wireguard.

themafia4• 7 months ago

Ironically there's T-Mobile Business which is static IPv4 only.

anonym292• 7 months ago

Not all of the skepticism is "does IPv6 work", some of it is "why should I want it as an end user who values privacy and minimal attack surface?"

From my perspective:

• CGNAT is a feature, not a bug. I'm already deliberately behind a commercial VPN exit node shared with thousands of others. Anonymity-by-crowd is the point. IPv6 giving me a globally unique, stable-ish address is a regression.

• NAT + default-deny inbound is simple, effective security. Yes, "NAT isn't a firewall", but a NAT gateway with no port forwards means unsolicited inbound packets don't reach my devices. That's a concrete property I get for free.

• IPv6 adds configuration surface I don't want. Privacy extensions, temporary addresses, RA flags, NDP, DHCPv6 vs SLAAC — these are problems I don't have with IPv4. More features means more things to audit, understand, and misconfigure.

• I already solved "reaching my own stuff" without global addressing. Tailscale/Headscale gives me authenticated, encrypted, NAT-traversing connectivity. It's better than being globally routable.

So yes, my parents are using IPv6 to watch Netflix. They're also not thinking about their threat model. I am, and IPv4-only behind CGNAT + overlay networking serves it well.

"It just works" isn't the bar for me to adopt IPv6. "It serves my goals better than IPv4" is the bar, and IPv6 doesn't meet it. Never has, never will.

IPv6 wasn't designed as "IPv4 with more bits." It was designed as a reimagining of how networks should work: global addressability as a first-class property, stateless autoconfiguration, the assumption that endpoints should be reachable. That philosophy is baked in. For someone like me, whose threat model treats obscurity, indirection, and minimal feature surface as assets, IPv6 isn't just unnecessary, it's ideologically opposed to what I want.

Want me to adopt a new addressing scheme? Give me a new addressing scheme, don't impose an opinionated routing philosophy on me.

oarsinsync4• 7 months ago

Anonymity-by-crowd is the point

Only for IP based trackers. Any webpages embedding facebook/twitter/microsoft/google trackers have already deanonymised you through a variety of fingerprinting techniques. This includes if you use private browsing sessions, and even qubesOS. You get a fuzzy feeling doing the things you do (and I do these things too), but that battle is lost.

NAT + default-deny inbound is simple, effective security … That's a concrete property I get for free

Depends on your definition of “free”. Is it cheaper to lookup just a connection state table, or is it cheaper to look up both a connection state table and a NAT table?

IPv6 adds configuration surface I don't want … More features means more things to audit, understand, and misconfigure.

100% agreed. More complexity, more attack surface, more things to go wrong.

I already solved "reaching my own stuff" without global addressing … It's better than being globally routable.

I do something like this too. It’s more private and more secure. It adds more complexity, and it restricts my ability to access things from terminals I don’t personally own & control unless I create another exposed vector though. “Better” is subjective based on metrics being optimised for.

IPv6 wasn't designed as "IPv4 with more bits." It was designed as a reimagining of how networks should work: global addressability as a first-class property

Apologies, but global addressability as a first-class property is exactly how the internet was designed. NAT was originally deployed as a hacky add-on to temporarily alleviate the lack of addressing space in IPv4 until a successor could resolve that.

That said, the internet of the 90s was a very different beast to the internet of today. A lot of your concerns and perspective is absolutely valid and extremely reasonable given the internet of today.

"It serves my goals better than IPv4" is the bar, and IPv6 doesn't meet it. Never has, never will … Want me to adopt a new addressing scheme? Give me a new addressing scheme, don't impose an opinionated routing philosophy on me.

IPv6 can absolutely be configured in ways that just gives you a new addressing scheme and does away with a lot of the other complexity. You’re just very much straying off the happy path, removing complexity by introducing … other complexity.

FWIW, I’m operating my home networks much the same way you do. I’ve also been dual stacking networks since the 2000s. Things have come a long way since the original pure-dogma introduction of ipv6.

pyuser583• 7 months ago

It’s still a pain to manage ipv6 AWS infrastructure via Terraform.

m4632• 7 months ago

I use ipv4 on my internal lan, and turn off ipv6

It is well supported, easy to configure, private, secure.

...and I don't have to configure and secure ipv6 in parallel

raffraffraff2• 7 months ago

This! I guess a good number of tech people will have IPv4 home networks long after their non-tech parents, neighbors and friends will be using IPv6 (without even knowing it).

IPv4 in the home is dead easy. You only need to remember the last digit (unless you've got multiple networks, but most won't). You can ssh to any device by remembering that ".1" is router, ".2" is NAS etc. Firewalls are simple.

You can buy a cheap domain and use it as your home DNS (eg "router.myhome.net" -> "192.168.0.1") so it works anywhere! In the home or roaming (over VPN). I don't really need to run DNS at home. My domain runs on Cloudflare DNS, my devices use NextDNS (with rebind protection disabled for my home domain).

I run OpenWRT and preallocate DHCP addresses for all known devices. Then I shrink the DHCP pool to a blacklisted range. A script automatically creates DNS records for all preallocated devices. If a new device appears in the blacklisted DHCP pool, I can manually allocate its MAC address a proper IP.

It's easy to get TLS certs for any service in the house using the ACME DNS01 challenge.

Tailscale is sexy and it worked fine until one day while roaming it wouldn't connect without "admin work", so I instantly dropkicked it. I'm now using the very unsexy OpenVPN Cloud (free for limited use) and in over two years it has never failed me. Plus it doesn't fuck with the IP addresses with fancypants tailnet addresses - I access devices directly using their DNS names which resolve to private addresses.

So, from inside or outside the home I can access the NAS to watch a movie, sync photos to Immich, print a document, check my IP cameras or ask my wife to put a document on the ancient scanner and access it via the raspberry pi phpscan website (which is on https://scanner.myhome.net)

I'm sure there's a very good reason not to do this and someone will now point it out.

josephg2• 7 months ago

Urgh I wish it were like that here in Australia! We have a fast, modern fiber internet connection in inner Melbourne. But my ISP still doesn't support IPv6 at all. I file a ticket about once a year, and I'm always met with more or less the same response - essentially that there's no demand for it.

I'd love to test all the internet services I host to make sure everything works over IPv6, but I can't. At least, not without using a 4to6 relay of some sort - but that adds latency to everything I do.

I just checked - apparently my ISP is "evaluating IPv6" because they're running out of IPv4 addresses and want to use CGNAT for everyone. I suppose its not the worst reason to switch to ipv6. But they've been making excuses for years. I really wish they'd get on with it.

whatevaa4• 7 months ago

I'm in Europe. My country ISPs have actually too many ipv4 addresses so zero ipv6 support at any of them.

chasing0entropy• 7 months ago

There so e obvious caveats that make ipv6 migration impossible for most users: 1. Ipv6 bridges are not practical at scale which means best case is dual use protocols for a decade (or more) which no one wants to support.

2. Actual implementation MUST be ubiquitous (it never will be) some examples - glo fiber in Virginia, and while I can get pfsense assigned a ipv6 address, there is usually no upstream gateway (meaning that if I disable IPv4, I will not have internet). I say usually because of four times I've checked, once I did get assigned a gateway which was unresponsive even to icmp.

Starlink roam - assigns ipv6 but no bridge so if you disable v4 you lose access to most internet.

Frontier FiOS in Florida - does not support ipv6 at all on my node. I have seen business nodes in Orlando/Tampa assign addresses with bridging but again, without browser or dns translation it's not a practical solution.

3. 'Everyone' is not using ipv6, everyone plugs in or logs into a device that has whatever network stack it has. Those users are not suddenly going to jump through hoops simply to avoid CGNAT and get a unique network address

4. Infrastructure; I have two modest half racks on the east coast at decent sized datacenters (esolutions and peak10), neither of those hosts offer ipv6 routing blocks by default. No provider I have gotten quotes for offers ipv6 by default

phil21• 7 months ago

I’m surprised home many technically knowledgeable people on Internet forums still think IPv6 is some niche, unreliable thing.

The more technically knowledgable you happen to be on the subject, the more you realize IPv6 is some unreliable thing when compared to IPv4. Perhaps no longer niche though.

It's unfortunately still an afterthought for many backbones - and not just US-centric ones. There is a noticeable difference in performance metrics from clients served via IPv4 endpoints vs. IPv6 for web assets in the same locations from the same transit providers.

It is pretty much the opposite of "just works" depending on your definition of "just works". It results in more Traffic Engineering per bit served by a large factor compared to IPv4.

1vuio0pswjnm72• 7 months ago

"I'm surprised home many technically knowledgeable people on Internet forums still think IPv6 is some niche, unreliable thing."

Where can we read some examples of this

I've read commentary about pros and cons of IPv6 over the years but never anything that suggested IPv6 was "niche" or "unreliable"

MaKey• 7 months ago

The comment from phil21 directly above yours calls IPv6 unreliable.

1vuio0pswjnm72• 7 months ago

NB. The requests is for examples that inspired the quoted statement

In order to have inspired the quoted statement these examples would have to be found in forum comments published before the quoted statement was made

Comments made in response to, i.e., after, the quoted statement would not qualify

evanjrowley• 7 months ago

Over the past 10 years, the majority of "my internet stopped working" cases have been solved by disabling IPv6. In each case, it's AT&T who for some reason can't seem to operate it reliably.

My own home is Verizon, and they simply do not offer IPv6 in my area (nearby Washington DC).

wolrah• 7 months ago

Don’t blame your provider when they deploy CG-NAT, embrace IPv6 and global routing instead.

In theory this makes sense, but in practice my personal experience is that not a single wireline ISP I've ever seen deploy CG-NAT offered IPv6 service at all, nor did any of them indicate any intent or even interest when asked about it.

The mobile providers on the other hand have almost entirely gone IPv6-first, using 6>4 transition methods as the default form of v4 access which I fully support.

4>4 CG-NAT should never have existed and providers who deploy it without offering fully functional v6 should be shamed.

suprjami• 7 months ago

World IPv6 day 6-6-26, just turn IPv4 off. Let the world catch up.

I said the same thing for 6-6-16 too.

zygentoma• 7 months ago

Uh, I like that!

I have some services on IPv6 only, but it rarely convinces anyone that they need IPv6 connectivity …

kachapopopow2• 7 months ago

the reason why I explicitely disable ipv6 cause "this shit don't work" (at the moment, will probably change in the future)

- random slowdowns

- horrible routing

- larger packet overhead

- hated by a lot of the people who run the internet

- hated by companies who provide ddos protection

- my poor TCAM cache in my budget routers

- supporting ipv6 is really expensive in chassis routers

However, I believe there is a solution: Swap ISP's to IPv6 only, swap to IPv4 unless there is an IPv6 route present then directly forward. This solves quite a few issues: Once every ISP has IPv6 you can drop ipv4 and swap directly to ipv6 without having to split your TCAM. This works because IPv6 can encode IPv4 in it.

kachapopopow2• 7 months ago

I guess I will add some clarification since this is still somehow getting traction:

- this is from speaking with various techs in the space and holding an ASN

- T1 ISP's will never put in the work to make switching to IPv6 easier.

Dylan168078• 7 months ago

Am I missing something? Where's the part where he actually talks about his experience in that week? This goes straight from an overview of IPv6 to the conclusions section.

flumpcakes5• 7 months ago

I'm very surprised by the questions in this thread. There are some extremely basic things people are just not understanding. I suspect people hating on IPv6 have not spent the time with it. There is a difficulty in that it does behave quite differently to IPv4, and the lack of private addresses are also probably a shock.

transcriptase2• 7 months ago

The basic thing proponents don’t understand is that nobody in their right mind can intuitively understand IPV6 addresses because they look like MAC addresses with trisomy and are a pain in the ass to remember or type for absolutely no benefit to the non-network engineer. And there are infinitely more people with home routers and a few dozen devices than there are people running ISPs, fortune 500s, and data centres. Play with your convolution all you want, in 20 years the rest of us will still be happily assigning 192.168.x.x and ignoring it. V4 space running out is no more the average persons problem than undersea cables or certificate authority.

Dylan168078• 7 months ago

nobody in their right mind can intuitively understand IPV6 addresses

If someone can't understand "it's longer" then what is wrong with them?

And using hex instead of decimal for magic computer numbers should be more intuitive, not less.

Also structure-wise the first half is the subnet and the second half is the host. That's much more intuitive than IPv4.

absolutely no benefit to the non-network engineer

If you do anything peer to peer at all, calls or file transfers or games, there's a benefit. And the typical benefit grows over time as more and more ISPs install CGNAT.

justsomehnguy2• 7 months ago

intuitively understand IPV6 addresses because they look like MAC addresses with trisomy and are a pain in the ass to remember or type

I have north of 500 IPs I have some relation to. No way I would be bothered to remember them. Typing? Do you type IPv4s all day long? And it's still copy-paste 99% of times.

for absolutely no benefit to the non-network engineer

Non-network engineer should work with names. And non-engineers don't 'work' with IPs at all. Look at your granpa - he's typing 'bbc' into the search form in the browser to get to bbc.com.

nobody in their right mind can intuitively understand IPV6 addresses

And 99% of so called engineers can't understand even IPv4. So this is a moot point.

ssl-32• 7 months ago

I agree.

It's easy to tell someone to connect to something like 203.0.113.88. Many of us here, and also normal folks, have been saying dotted-octets like that for decades, now, and there's a familiar patter to the way that addresses like this flow off of the tongue.

It's hard to tell someone to connect to 2601:3c7:4f80:1a01:4d2:3b7a:9c10:6f5e. It's literally difficult to say, like saying it is intended to be some kind of test. And on the other end? Sure, we "all" "learned" hexadecimal at some point in school, but regular humans don't use hex so it sounds like missile launch codes (at best) or some kind of sadistic prank (at worst) to them. It reeks of phonic unfamiliarity and disdain.

(This is the part where the DNS folks invariably show up to announce that I'm holding it wrong. And I love DNS; I do. But I'm really not interested in maintaining public DNS for the dynamic addresses at home on my LAN.)

(After that, it becomes time for the would-be abbreviators to appear and tell me that the address for this computer is wrong, somehow, as if I ever had an active part in selecting the address to begin with.)

themafia4• 7 months ago

There is a difficulty in that it does behave quite differently to IPv4

Which can be fine if you have a /solid/ transition plan to move networks wholesale from v4 to v6. They absolutely failed on this point and almost purposefully refused to carry over any familiar mechanisms to make dual stack easier to manage.

It's a University protocol that escaped into commercial usage based mostly on false fears of global routing table size becoming unmanageable or impossible to store in RAM. The results are absolutely predictable.

tgsovlerkhgsel• 7 months ago

I haven't spent a lot of time with my power grid either, but I do expect the light to go on when I press the switch.

(Needing to dedicate time for it is, to some extent, either a failure of the protocol or at least a contributor to the lack of adoption.)

flumpcakes5• 7 months ago

In my experience IPv6 has always "just worked" for me in the consumer space. The only difficulty I have found is when implementing it into an existing managed network. Most organisations will not touch it, they're too comfortable with IPv4, unfortunately.

1970-01-012• 7 months ago

I have firsthand experience doing that experiment about 3 months ago. Completely removed my IP4 DHCP lease from my ISP at the router. About 50% of the public sites I tried to visit didn't resolve. So many public sites, that I gave up and went back to dual stack after just a day. Google, ChatGPT, and a few other popular sites were fine with pure IPv6 traffic, however sites like eBay and even HN did not resolve. IPv6 simply is still not ready for everyone to just transition into overnight.

whatevaa4• 7 months ago

A bit ironic that HN did not resolve.

mightyham6• 7 months ago

Peer-to-peer communications such as gaming usually have to deal with NAT traversal, but with IPv6 this is no longer an issue, especially for multiple gamers using the same connection

You know the list of "benefits" is thin when the second item is entirely theoretical. Even though IPv6 doesn't have to do NAT traversal, it still has to punch through your router's firewall which is effectively the same problem. Most ISP provided home routers simply block all incoming IPv6 traffic unless there is outbound traffic first, and provide little to no support for custom IPv6 rules.

Even if that were not an issue, my bet is that there are close to zero popular games that actually use true peer to peer networking.

brigade• 7 months ago

Getting a streamer’s IP attracts DDoSes and doxxing, so yeah it’s generally considered a vulnerability to use P2P in games

whatevaa4• 7 months ago

Yeah, p2p is fine only with friends, people you know, otherwise it's like posting your private address for everybody to see.

justaboutanyone2• 7 months ago

Punching through just a firewall is much easier than punching through a typical NAT+firewall setup

https://tailscale.com/blog/how-nat-traversal-works

whatevaa4• 7 months ago

How do you punch trough firewalls? You have to manually open them, punching through firewall would be a firewall vulnerability.

mightyham6• 7 months ago

You're just asserting that without explination. Please correct me if I'm wrong, but afiak the only difference in NAT hole-punching is that clients don't know their public port mapping ahead of time. This actually doesn't make a huge difference to the process because in practice, you still want a central rendezvous server for automated peer IP discovery. The alternative being that each peer shares their IP with every other peer "offline", as in manually through an external service like IRC or discord, which is a horrible user experience.

trashtensor• 7 months ago

Not having a congested CGNAT in the mix at 4pm every day is a nice benefit.

themafia4• 7 months ago

it still has to punch through your router's firewall

That's why most routers use a stateful firewall. Then nothing has to "punch through" it just has to be established from the local side.

block all incoming IPv6 traffic unless there is outbound traffic first, and provide little to no support for custom IPv6 rules.

This is why STUN exists.

my bet is that there are close to zero popular games that actually use true peer to peer networking.

For game state? You're probably right. For low latency voice chat? It's more common than you'd think.

ruszki• 7 months ago

The complication starts when such an ephemeral port gets connection from somewhere else, which is the crucial part not the creation of such ports. That is not supported necessarily by firewalls, or not that simple than just having a stateful firewall.

mightyham6• 7 months ago

it just has to be established from the local side

This is exactly the problem. Unless you expect users to manually share their IPs with every other user in a given lobby through an external service, you would need to make a central peer discovery and connection coordination mechanism which ends up looking pretty similar to classic NAT traversal.

Spivak• 7 months ago

Also NAT66 exists and I use it on my home network so you still have to have the machinery to do NAT traversal when needed. It's nice to use my public addresses like elastic IPs instead of delegating ports. IPv6 stans won't be able to bully their way into pretending that NAT doesn't exist on IPv6.

ChrisMarshallNY6• 7 months ago

I'm pretty underwhelmed by IPv6. It looks like the typical "horse designed by committee."

I suspect that what will actually end up being implemented, will be a core subset of the spec.

We'll have to see what's still standing, when the dust settles.

db48x10• 7 months ago

Your computer, and every other computer on the planet, already supports the entire IPv6 spec. There is no subset.

ChrisMarshallNY6• 7 months ago

Well, we'll have to see what all the "in-between" bits do. There's a lot in it, that will require implementation by countless layers of routers, switches, caches, firewalls, etc.

Look at Bluetooth, for an example, or TIFF.

I printed out the Bluetooth spec once, just for Ss and Gs. It was over 2,000 pages (double-sided).

I once tried writing a fully-compliant TIFF reader. Didn't go so well.

yjftsjthsd-h5• 7 months ago

I'm typing this on a computer running Android, which means it doesn't support DHCPv6. I would describe it as supporting a subset of IPv6 functionality.

jeroenhd4• 7 months ago

The IPv6 spec looks long because it also includes protocols that are separate on IPv4 (DHCP/SLAAC, NDP, depending on the document ICMPv6, mirroring DHCP, ARP, ICMP, NetBIOS, etc.), as well as the addressing schemes that were different RFCs in IPv4 such as multicast/unicast/network classes/subnets.

As for the implementation: just about anything more powerful than an ESP32 has the entire protocol implemented and running already.

ChrisMarshallNY6• 7 months ago

As long as the SDKs to apps make it simple, we'll be good. I haven't seen much, so far.

imathew• 7 months ago

My ISP has good IPv6 support. I was using it for a while and recently disabled it across my home network for simplicity of maintenance, cutting my vyos config in half. When I need to access something not available on IPv4 I'll set it up again but I'm not convinced that will happen in my lifetime.

seviu• 7 months ago

And despite that, the place where I work, has disabled ipv6, rendering our development machines useless for trivial tasks such as debugging our iOS app on a device (which uses ipv6 under the hood)

Reasons given: the security policies say ipv6 is not safe enough.

razighter777• 7 months ago

The workarounds we need to enable P2P communication on the internet are a shame... we need turn, stun, webrtc, all this stuff so two computers can talk without a dedicated port forward or public ipv4.

ipv6 is a beautiful protocol, (not perfect, but elegant) with a lot going for it. But the momentum of ipv4 is just too strong.

It's a mess... with no good solution. I tried to turn off ipv4 and github (shame on you) stopped working. But what are we supposed to do? Have the government mandate everyone switch? (oh wait half of US government websites are ipv4 only)

We did this to ourselves...

dpkirchner2• 7 months ago

I try enabling IPv6 every year or so. The last time I tried IPv6 at home I couldn't figure out what my netmask was, nor the size of my allocation. Some folks say my ISP issues /60s, others /64. I couldn't figure out how to get my IP to remain static long enough to have long-running TCP sessions, either. It was a mess and not much better than it was 20 years ago when I first tried it (and had to disable it because it being on broke all sorts of things).

Maybe 2026 will be the year of IPv6. I kinda doubt it given I'm some jackass and dedicated network professionals still don't use IPv6.

illusive40805• 7 months ago

If you have ATT fiber, it’s a pain in the butt. Their default router will only issue a single passthrough /64 on request. If you have multiple VLANs you have to setup some scripts to ask for more, and even then you only get 8 of them. The gateway reserves the other 8 from the /60 it gets for its own use.

The only way I got IPv6 working well with them was to bypass their gateway. Now all my VLANs have /64, which is the standard subnet size.

ekropotin4• 7 months ago

I think bypassing their gateway, that is - bringing your own router is the only way to do VLANs, because their gateway is very basic and doesn’t support VLANs at all.

ianburrell4• 7 months ago

Why are you setting up anything? You turn on IPv6, the router figures out its prefix from the upstream router, and then router broadcasts the network to devices.

The netmask for IPv6 is nearly always /64. ISPs give out /60 to allow multiple subnets, but router makes /64 subnets from that.

topranks4• 7 months ago

Nah. There are lots of things you’ll need to know.

Does it use SLAAC on the WAN side or DHCPv6? How do I get a range for my lan then, DHCPv6 prefix-delegation? Or maybe it’s statically assigned somehow. Some carrier’s just use link-local ok the WAN, with no public v6 just RAs for the link-local, and a GUA block via IA_PD.

Regardless there are too many ways this is done, and this hampers adoption as it’s not just the “switch it on” operation you suggest.

ninkendo5• 7 months ago

Not OP, but when I first tried to learn IPv6 for my home internet, I found that it's very important that you get the DHCP-PD prefix size right when configuring your router, or it would just not work at all.

I have Comcast, and they do give me a /56, but you can't ask for a /56 in the DHCP-PD request, because they don't support a single request grabbing all of your prefix space. You have to ask for /60's, which I had to find out through trial and error.

But it may have been even worse (my memory is fuzzy) because I think at one point I did successfully get a /56, but that then exhausted my DHCP allocation, and then after I rebooted my router I couldn't get anything any more. It didn't help that the router I had been using (Unifi security gateway) didn't seem to keep a static DUID that comcast was happy with, so I kept getting new prefixes every time it rebooted.

Comcast probably has so few customers that bring their own cable modem/router at this point that they basically don't have any support for this, you won't get anything from them over the phone, they just push you to pay them to rent their equipment (where they configure all these parts the way their network expects.) You have to be adventurous to run your own equipment with IPv6.

dpkirchner2• 7 months ago

I need to know what IPs they might assign to my network, and then what IPs are to be assigned to my computers (or what I can assign statically).

topranks4• 7 months ago

Probably the largest barrier to IPv6 adoption is the myriad ways IP allocation to clients can be done and the various options that exist.

It’s fine for mobile providers, where the client activation defines what’s needed and the carrier essentially just needs to support two OS’s (iOS and Android).

Also mostly fine for residential when the carrier provides the CPE, and can set it up to work with how they have the network built.

But if you’re managing your own router it can be complex to know exactly what to use. And most ISP support aren’t very good either.

If you happen to be an expert it’s fine, but if you’re a power user not a full time network guy there is still way more complexity than there ought to be.

ctippett• 7 months ago

Every few years I check to see how far away Virgin Media are from offering IPv6. Just checked again... nope!

https://www.havevirginmediaenabledipv6yet.co.uk/

daft_pink• 7 months ago

I feel this doesn’t really address whether we are losing something privacy or security related by not having NAT. I think my main devices are always updated Mac iPhone or iPad and can handle it, but do I really want my thermostat or doorbell or lock or garage door opener or light switch directly accessible on the Internet or is the nat serving a useful purpose? I don’t feel like this is addressed in this article.

yjftsjthsd-h5• 7 months ago

but do I really want my thermostat or doorbell or lock or garage door opener or light switch directly accessible on the Internet or is the nat serving a useful purpose?

You should have a firewall, regardless of v4/v6.

mzajc2• 7 months ago

You should, but the exposure from having no firewall is much higher without NAT. Packets with private network IPs are martians on the internet and will not find their way to your device unless they come from the same network and the ISP's infrastructure doesn't drop them. IPv6 addresses are routable across the internet so the packets will most likely get to your router, meaning anyone on the internet can talk to your LAN in the absence of a firewall.

The reality is that consumer router firmware is horrible in every aspect, especially security, and this isn't going to change with IPv6 rollout. I fear the most likely scenario is that ISPs will set up inbound firewalls on their end, and then we'll be even worse off than we are right now.

martinald• 7 months ago

Interesting. I did finally find a use for IPv6 which I wrote up here: https://martinalderson.com/posts/i-finally-found-a-use-for-i...

Tbh though the docker problems are very serious and extremely painful to work around. Everything works great apart from Docker which has so many issues - it does not handle IPv6 inbound but IPv4 out well at all (at least as far as I can tell!).

transitorykris• 7 months ago

In my 25 year career in network engineering, I’ve encounter needing it as a user exactly once, and that was earlier this year. Supabase’s free tier allows direct connections the Postgres only over IPv6. It’s too bad the deploment has been a long drawn and expensive process for everyone.

yjftsjthsd-h5• 7 months ago

I spent a WEEK without IPv4 to understand IPv6 transition mechanisms
NAT64 - the method I’ve setup for this test
IPv6 is absolutely ready for prime-time and has been for awhile

So... No, you spent a week effectively using both v6 and v4 with extra steps. If someone said "Linux is ready for primetime" but their setup only worked because they ran a bunch of applications in a Windows VM, I'd call that strong evidence that it really wasn't. Same here.

That said... This is from early 2023. Any chance it's better now?

rendaw• 7 months ago

None of the ISPs where I live provide NAT64 gateways. Exactly one advertised it, I signed up almost a year ago and they still haven't enabled it for me yet (I think they don't actually offer it and just forgot to remove the page).

eqvinox• 7 months ago

That said... This is from early 2023. Any chance it's better now?

I accidentally went IPv6 only on my home wifi for a few weeks a while ago. I only noticed when GitHub didn't load (I avoid work things at home, hence accessing GitHub being rare.)

Relatedly, fuck GitHub and their incompetence at rolling out IPv6. It's nothing other than that at this point. Blank, unadulterated incompetence.

topranks4• 7 months ago

No, because unfortunately the need for v4 hasn’t changed. In other words many sites and parts of the internet remain only on v4.

Until nearly everything is on v6 too it won’t be realistic to ditch the mechanisms that provide v4 access.

lmm• 7 months ago

No, you spent a week effectively using both v6 and v4 with extra steps.

It's less steps though. You can do all your network setup in the nice v6 world, and set up v4 emulation for those who need it. Yes, it's not yet practical to turn of v4 entirely, just like it's not yet practical to turn off Rosetta on your ARM mac.

imrejonk• 7 months ago

My former colleague Marco Davids from SIDN Labs (the R&D department at the .nl TLD operator) did an experiment in 2021 where he actively disabled IPv4 support on all components in his test network, even disabling the complete IPv4 stack in the FreeBSD kernel (not possible on Linux, at least not at the time). So far, his test is the only thing I know of that came close to an authentic simulation of an IPv6-only world.

https://www.sidnlabs.nl/en/news-and-blogs/can-we-do-without-...

1970-01-012• 7 months ago

AAAA record resolution is the real bottleneck for adoption. Once you have dual stack working, I did a real-world, simple test: Release your ISP IPv4 DHCP lease on the router (kill udhcpc) and flush DNS on your hosts. Now all public DNS lookups must resolve to a IPv6 domain. You will very quickly find many domains on the Internet still don't have AAAA records. Lots of popular services will simply fail to resolve their hard coded domains. QED.

https://whynoipv6.com/

self_awareness• 7 months ago

My ISP has IPv6 since years and I'm on 6 as well.

NAT-less network is really cool, I can serve content directly from anything from my LAN.

We should really leave IPv4 and move on.

sneak• 7 months ago

I tried that, but my HN addiction ended it.

ianburrell4• 7 months ago

HN has IPv6 now.

If Reddit would finish adding IPv6, almost all of my browsing would be IPv6.

illusive40805• 7 months ago

AWS doesn’t offer PTR records for IPv6 addresses, which makes Gmail blacklist my email server’s IPv6 address. I had to disable IPv6 due to lack of PTR records.

buggjenrmf5• 7 months ago

Not being able to setup a spam server in aws is a feature.

illusive40805• 7 months ago

It’s not a spam server. I self host email for personal and non marketing business use. Don’t assume everyone running their own email is a spammer.

topranks4• 7 months ago

Dual-stack with a public IPv4 address is by far a preferable way to access the v4 internet than being stuck behind a provider NAT64 box.

Totally understand why carriers may want IPv6 mostly and a v4-free core. But as an end user dual stack just seems simpler.

jcgl7• 7 months ago

Providers can do v6-only in their core while still providing public v4 to users. SIIT if they can still afford a public IP per customer, and MAP-T if they can’t.

jcgl7• 7 months ago

Misspoke: more like a CLAT thing/464XLAT, rather than SIIT, I think

beAbU• 7 months ago

My previous fibre provider in Ireland was Virgin, and as far as I could tell, it was fully IPV6. Every device in my network got a public address, and self hosting stuff from home as was easy as setting up an A record at my DNS host. No faffing around with port forwarding, proxying, nat bullshit or whatever. My memory is hazy, but there might have been some firewall stuff I had to do on the virgin supplied router.

torcete• 7 months ago

I wonder about the possibility of running your own email server behind a domestic IPv6 address.

Most of the domestic IPv4 networks have port 25 blocked for incoming connections. Maybe in the IPv6 realm things are bit more relaxed.

I spent a week without IPv4 (2023)

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