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::: spoiler transcript From: Linus Torvalds torvalds@linux-foundation.org To: linux-kernel@vger.kernel.org Subject: [RFC] Remove IPv4 support from kernel, effective next merge window Date: Sat, 15 Aug 2025 10:42:00 -0700 Message-ID: 20250815-drop-ipv4@linux-foundation.org

Hey folks,

After yet another deeply technical and entirely calm discussion about HRT (High-Resolution Timers) that somehow devolved into 200+ replies, personal insults, and at least one GIF of a raccoon, I have decided it’s time to take drastic measures.

Effective next merge window, we will be removing IPv4 support from the kernel. This will both (a) resolve the maintainers’ scheduling disputes, and (b) force the world into the IPV6 utopia we were promised back in 1998.

If you need IPv4 after this point, you can either:

run an ancient kernel from before the change (good luck with the bugs), or rewrite your applications to use IPv6 and learn to love colons in your addresses. Yes, I realize this will break roughly *everything *. No, I don’t care. I have already switched all my machines to IPv6-only, except for the toaster, which unfortunately still insists on using a 192. 168. x. x address. The toaster will be replaced.

If you disagree with this decision, I suggest you take it up with the HRT maintainers. But please keep it civil this time. (Or at least keep the raccoon GIFs under 1MB.)

• Linus :::

Not really.
https://lemmy.dbzer0.com/pictrs/image/22c957e6-b371-4cb9-8eae-2ea248fe9d45.webp Source: https://rivals.space/@deuxnise/115032302416832519 Originally posted here

uhhh, don’t look too close at the dates in the email.

God I fucking wish. I hate ipv6 but I hate this split world even more. Nothing but headaches.

Based and v6 pilled.

Finally some welcome news. I’m tired of simple easy to understand addressing.

Not even the most controversial HRT.

I forgot what day it was.

Were any toasters harmed in the making of this toast post?

Odd day for him to post this…..

How can anyone even be bothered doing 1st April anymore with everything going on?

Embrace hexspeak.

Sounds like a Microslop Copilot decision.

Also, DNS is now depricated and will be removed in the merge window after the ipv4 removal. This will fix 90% of all networking problems.

You did check today’s date?

Look at the date.

I really gotta see this racoon gif

Me too. This is the only one that fooled me at first today. Ill take it. If you have to make a joke about ip addresses and the kernel to fool me, then I guess I’m still pretty sharp.

It may be inevitable, but if you wonder why ipv6 has been slow to adopt, it’s because no one want to type in 32 alphanumeric digits for every single device, every time…

Now that’s some April Fools trolling done right.

I mean I did say I hate ipv6…

But seriously, I think it has more to do with it’s slightly different, easier for ISPs to just add another NAT layer or whatever instead of learn the minor differences.

Just give OpenClaw unrestricted access to your system and make the AI do it. /s

The kernel doesn’t deal with DNS, that is a separate process/library

Honestly, I get this is a joke…but it unironically wouldn’t impact me, I run single stack v6, so let’s do it. I’ll grab some popcorn

HRT :3

If we magically got rid of IPv4, I do wonder if the world would decay to a state of utter chaos like the tabloids were touting for Y2K

HRT :3

Also gives them more control, and they can charge extra for open ports.

I was dying with suspense wondering if he would weigh in on that.

I’m slowly moving in the direction and have learned a lot, but in my home network, all my devices get a bunch of IPs and services seem to choose at random the IP to listen on. My ISP changes my prefix at random. Devices don’t register in DNS. So even if I use the ULA it’s a lot of fucking typing.

I also had this thing for a while where the MAC of a bhyve VM would change at boot so even the ULA changed. That fucked me for a while.

Opnsense lets me create aliases allowing me to create firewall rules, so at least that works now… kinda. But i haven’t figured out privacy extensions.

So yes, you’re right, 32 digits is a lot to keep in mind.

Isn’t like 50% of the internet broken for you if you’re only running IPv6? It seems like so many websites , especially small ones, still aren’t setting up v6 addresses

What’s going on?

That’s why I posted it.

the only truth when it comes to which type of hrt is better is this:

any hrt >>>>> no hrt

The amount of stuff that supports ipv6 is huge, however as most ISPs still don’t know how or want to know how to support that would be the problem. So the internet would be fine apart from a couple of sites, but I’d guess 50-80% of home/business connections would fail.

However most mobile carriers are ipv6 native or close to it, so everyone can get on Facebook and tiktok

NetworkManager now has a CLAT and you can install clatd if not using nm.

But Linux is a bit behind on this tbh, especially compared to MacOS/iOS and Android (to a lesser extent) which have had mature clat support for years.

Small ones are actually often better than big ones. I have a love hate relationship with cloudflare, they contribute to internet centralization but it IPv6 enables so many sites transparently and they only let you turn it off if you’re an enterprise customer. So some guy using free cloudflare has IPv6 but not discord, ironic. That being said I have NAT64+DNS64 which lets me access the remaining legacy v4 services without having v4 on my network or devices. Although according to my firewall stats over 90% of my traffic is v6 native, the remainder is NAT64. Honestly the only services I use on a regular basis which don’t work if I disable NAT64, discord, steam, and my bank. Everything else I use is v6 native, YT, Crunchyroll, lemmy (this instance), even steam downloads (just not login ironically).

it’s because no one want to type in 32 alphanumeric digits for every single device, every time…

Use DNS; I almost never type in an IP manually. You can also make short IPv6 addresses that are just the prefix and a bunch of zeros using ‘::’ followed by one character.

Something like:

2001:0DB8::1

Damn, you didn’t even need to fake it, it’s already happening: https://lore.kernel.org/lkml/20260401074509.1897527-1-dwmw2@infradead.org/

Sure it’s still just a joke, but there is a follow up:

The date notwithstanding, I do actually think we should do most of this for real.

• https://lore.kernel.org/lkml/2cb91533e22ed6cb11205dbc56b8aeedbbce0cca.camel@infradead.org/

On this day of global reconciliation, they should split the difference and go for ipv5.

I tried to do this but am too old, too dumb, or a little bit of both. Shine on my dude, if there’s any resources you found particularly helpful I’d love to see them. Got as far as getting an address from my isp but couldn’t even ping it x(

Picket lines and picket signs
Don’t punish me with brutality

I wish

They would get fixed quickly if they were forced to

Calling IPv4 “easy” is a weird take

If you are typing 32 chars for a IPv6 address you are doing it wrong

2001:db8::1

Fixed it for you

You could just assign private IP

In IPv6 land you can have infinite amounts of addresses including pone or more private addresses.

Large ISPs with limited IPv4 use a ton of IPv6

Its the small shops and ancient companies that are the problem.

Nice try nerd

That’s how we got the Ellipse of Hormuz

nm, hbu

You mean IPvV?

I prefer the combination of IPv4 and IPv6 as a Dual Stack, call it IPvX.

I was hoping they drop TCP/IP scam finally… But no. The only network protocole you need is rina.
Many have already make the step, learn about it right now to be ready for the futur.

IPvX = IPvIV + IPvVI

Yeah, we have mDNS for a reason.

Or even just link the DHCPv6 server to the DNS, that’s the default config in most cases anyway.

HRT maintainers? So trans people?

For the hyper text TRANS port layer (the socks)

ipv4 does not deserve the hate it gets. The congestion caused by the small number of ipv4 addresses is actually really good for privacy, and makes ip based tracking very difficult.

Mind = blown

Aproofoools

Maybe we drop ethernet all together and go back to tokenring?

Only in non-Euclidean geometry.

The internet is just a fad anyway

wrong layer

Good one

I should’ve said “did you all check today’s date”.

On the complex plane.

i = (1÷Md)×blow

Ahh… so the Unix socks people. Glad we could clear up that ambiguity.

That’s why IPv6 has privacy extensions which periodically rotate your address