[HN Gopher] New patches allow building Linux IPv6-only
       ___________________________________________________________________
        
       New patches allow building Linux IPv6-only
        
       Author : Bender
       Score  : 111 points
       Date   : 2026-04-01 13:15 UTC (9 hours ago)
        
 (HTM) web link (www.phoronix.com)
 (TXT) w3m dump (www.phoronix.com)
        
       | rafaelcosta wrote:
       | As it should. Date notwithstanding, I would actually enjoy if
       | there was a manually induced latency penalty for "legacy IP" that
       | needs to be manually turned off on Linux. I know some people
       | don't care at all, but the internet was made to be addressable.
       | IPv6 is the only shot we have to go back to that.
        
         | nslsm wrote:
         | This reminds me of the ways the governments screw over people
         | to force them to do things they don't want to.
        
           | lxgr wrote:
           | Annoying things such as paying taxes, recycling/not polluting
           | etc.?
           | 
           | Some things really can only be solved via central
           | coordination, as there is no natural game-theoretic/purely
           | economic path from one local minimum to another. Being able
           | to dig a small trench and letting gravity and water do the
           | rest is great, but sometimes you do need a pump.
           | 
           | I'm not convinced that IPv6 is such a case, but if it is,
           | that's exactly the type of thing governments are much better
           | at than markets.
        
         | huijzer wrote:
         | Please no. I used to have a Dutch ISP a few months ago that did
         | not support IPv6 yet. (Odido. Same ISP that leaked my data in a
         | big hack.)
        
           | jeroenhd wrote:
           | Odido is the cheapest ISP for a reason. They refuse to
           | implement anything that isn't strictly required.
           | 
           | Perhaps implementing an Odido tax might actually make Odido
           | care enough to throw the switch on IPv6. They bought
           | 2a02:4240::/32, they just refuse to make use of it.
        
             | miyuru wrote:
             | they do use it in their speedtest server.
             | curl -v https://speedtest.ams.t-mobile.nl.prod.hosts.ooklas
             | erver.net:8080       ...       * Connected to
             | speedtest.ams.t-mobile.nl.prod.hosts.ooklaserver.net
             | (2a02:4240::e) port 8080
        
               | embedding-shape wrote:
               | Probably a requirement from Ookla, so again "They refuse
               | to implement anything that isn't strictly required".
        
             | kingstnap wrote:
             | > They refuse to implement anything strictly required
             | 
             | This describes a lot of businesses ngl.
             | 
             | Bell in Canada is one huge head scratcher. They are one of
             | the largest ISPs here and I can even buy 8 gig internet to
             | my house if I want but they don't support IPv6.
        
               | bombcar wrote:
               | Apparently (according to techs) a lot of ISPs are like
               | that - they said they have everything up and running and
               | even tested to turn on IPv6 but they haven't received the
               | go-ahead.
               | 
               | He mentioned this because marking my connection as a
               | "business" one without changing anything else would allow
               | it to get IPv6 (a /64, bah).
        
           | Sanzig wrote:
           | Canadian ISPs are also extremely far behind on IPv6. Bell is
           | the largest ISPs in the country and they still don't have
           | IPv6. I'm with one of their wholly owned subsidiaries (EBOX)
           | which offers static /56 allocations, but good luck trying to
           | find anyone in tech support who understands WTF you're
           | talking about.
        
         | everdrive wrote:
         | - I don't want my interfaces to have multiple IP addresses
         | 
         | - I don't want my devices to have public, discoverable IPs
         | 
         | - I like NAT and it works fine
         | 
         | - I don't want to use dynamic DNS just so I have set up a
         | single home server without my ISP rotating my /64 for no reason
         | (and no SLAAC is not an answer because I don't want multiple
         | addresses per interface)
         | 
         | - I don't need an entire /48 for my home network
         | 
         | IPv6 won't help the internet "be addressable." Almost everyone
         | is moving towards centralized services, and almost no one is
         | running home servers. IPv4 is not what is holding this back.
        
           | doubled112 wrote:
           | I recently changed ISPs and have IPv6 for the first time. I
           | mostly felt the same way, but have learned to get over it.
           | Some things took some getting used to.
           | 
           | An "ip address show" is messy with so many addresses.
           | 
           | Those public IPs are randomized on most devices, so one is
           | created and more static but goes mostly unused. The randomly
           | generated IPs aren't useful inbound for long. I don't think
           | you could brute force scan that kind of address space, and
           | the address used to connect to the Internet will be different
           | in a few hours.
           | 
           | Having a public address doesn't worry me. At home I have a
           | firewall at the edge. It is set to block everything incoming.
           | Hosts have firewalls too. They also block everything. Back in
           | the day, my PC got a real public IP too.
           | 
           | NAT really is nice for keeping internal/external separate
           | mentally.
           | 
           | I'm lucky enough my current ISP does not rotate my IPv6
           | range. This, ironically, means I no longer need dynamic DNS.
           | My IPv4 address changes daily.
           | 
           | A residential account usually gets a /56, what are you
           | talking about? Nowhere near a /48! (I'm just being funny
           | here...)
           | 
           | There are reasons to need direct connectivity that aren't
           | hosting a server. Voice and video calls no longer need
           | TURN/STUN. A bunch of workarounds required for online gaming
           | become unnecessary. Be creative.
        
             | bornfreddy wrote:
             | > Having a public address doesn't worry me. At home I have
             | a firewall at the edge. It is set to block everything
             | incoming.
             | 
             | Concern is privacy, not security. Publicly addressable
             | machine is a bit worse for security (IoT anyone?), but it
             | is a lot worse for privacy.
        
               | Guvante wrote:
               | You already have a public IP address the only difference
               | is if you have a rotating IP address which is orthogonal
               | to IPv6.
               | 
               | The only difference is most ISPs rotate IPv4 but not
               | IPv6.
               | 
               | Heck IPv6 allows more rotation of IPs since it has larger
               | address spaces.
        
               | bombcar wrote:
               | IPv6 can "leak" MAC addresses of connected devices
               | "behind the firewall" if you don't have the privacy
               | extensions / random addresses in use.
               | 
               | There are a number of footguns for privacy with IPv6 that
               | you need to know enough to avoid.
        
               | craftkiller wrote:
               | Privacy extensions are enabled by default on OSX,
               | windows, android, and iOS:
               | https://ipv6.net/guide/mastering-ipv6-a-complete-guide-
               | chapt...
               | 
               | On Linux, I think the defaults are left up to the distros
               | so there is a chance of a privacy footgun there.
               | Hopefully most distros follow the example set by Apple
               | and Microsoft (a sentence I never thought I would
               | write...)
        
               | bombcar wrote:
               | They are now - I'm not sure when they implemented them
               | but I know Windows at least would do some really stupid
               | stuff very early on.
        
               | zekica wrote:
               | All desktop/mobile OSes today use "Stable privacy
               | addresses" for inbound traffic (only if you are hosting
               | something long-term) and "Temporary addresses" for
               | outbound traffic and P2P (video/voice calls, muliplayer
               | games...) that change quickly (old ones are still
               | assigned to not break long-lived connections but are not
               | used for new ones).
        
               | everdrive wrote:
               | I'm not confused about the NAT / firewall distinction,
               | but it might be nice if my ISP didn't have a constant,
               | precise idea of exactly how many connected devices I
               | owned. Can that be _inferred_ with IPv4? Yes, but it's
               | fuzzier.
        
               | doubled112 wrote:
               | Is this solved by the device having between 1 and X
               | randomly generated IPv6 addresses?
               | 
               | Some of my devices have 1, some 2, and some even more.
               | Takes some precision out, at least.
        
               | wredcoll wrote:
               | Aren't your home addresses assigned by your local router?
        
               | iso1631 wrote:
               | the ISP can see 58 different ipv6 addresses sending
               | packets in the last hour
               | 
               | With ipv4 it can see one ipv4 address
               | 
               | Now sure that 58 could all be on one device with 58
               | different IPs and using a different one for each
               | connection
               | 
               | In reality that's not the case.
        
               | XorNot wrote:
               | Okay but why does this matter? They're your ISP they also
               | have your address, credit card number and a technician
               | has been in your home and also supplied the router in the
               | common case.
               | 
               | The theoretical vague problem here is being used to
               | defend a status quo which has led to complete
               | centralization of Internet traffic because of the
               | difficulty of P2P connectivity due to NAT.
        
               | vel0city wrote:
               | The ISP still doesn't know how many devices are
               | connected, because a lot of those devices are using
               | randomized and rotating IPs for their outbound
               | connections.
        
               | justsomehnguy wrote:
               | With SLAAC and a random IPv6 you would get at least the
               | same level of privacy. One public IPv4 isn't different
               | from /48 IPv6 network.
        
           | t0mas88 wrote:
           | IPv4 is not holding back home setups, nobody cares about NAT
           | at home.
           | 
           | The place where it hurts is small VPSs, from AWS to mom and
           | pop hosters, the cost of addresses is becoming significant
           | compared to low cost VPSs.
        
             | lxgr wrote:
             | > nobody cares about NAT at home.
             | 
             | Only because most people don't know how NAT is hurting
             | them, and because corporations have spent incredible
             | resources on hacking around the problem for when peer to
             | peer is required (essentially only for VoIP latency
             | optimization and gaming).
             | 
             | NAT hurts peer to peer applications much more than cloud
             | services, which are client-server by nature and as such
             | indeed don't care that only outgoing connections are
             | possible.
        
               | LegionMammal978 wrote:
               | Even in a NAT-less world, the common advice is to use a
               | firewall rule that disallows incoming connections by
               | default. (And I'd certainly be worried if typical home
               | routers were configured otherwise.) So either way, you'd
               | need the average person to mess with their router
               | configuration, if they want to allow incoming P2P
               | connections without hole-punching tricks. At best, the
               | lack of NAT might save you an address-discovery step.
        
               | lxgr wrote:
               | > the common advice is to use a firewall rule that
               | disallows incoming connections by default.
               | 
               | That's good advice! But firewall hole punching is also
               | significantly easier (and guaranteed to work) compared to
               | NAT hole punching. Address discovery is part of it, but
               | there are various ways to implement a NAT (some
               | inherently un-hole-punch-able) and only really one sane
               | way to do a firewall.
               | 
               | > you'd need the average person to mess with their router
               | configuration,
               | 
               | At least with IPv6, that firewall is likely to exist in
               | the CPE, which sophisticated users can then ideally open
               | ports in (or which can implement UPnP/NAT-PMP or whatever
               | the current name for the "open this port now!!" protocol
               | of the decade is); for CG-NAT, it's often outright
               | impossible.
        
               | bombcar wrote:
               | UPnP has covered a huge percentage of use cases that
               | actual users care about, and those who it doesn't cover
               | are often able to do their own customization.
        
               | zadikian wrote:
               | upnp should not exist. Any new router default disables
               | it, as it should be.
        
             | UltraSane wrote:
             | NAT is hurting anyone who has to use CGNAT and share an IP
             | with a bunch of other people.
        
             | Dylan16807 wrote:
             | Plenty of people care about CGNAT making it impossible to
             | connect to them.
        
           | Guvante wrote:
           | NAT only matters in so far as you don't technically need a
           | firewall to block incoming traffic since if it fails a NAT
           | lookup you know to drop the traffic.
           | 
           | But from a security standpoint you can just do the same
           | tracking for the same result. That is just technically a
           | firewall at that point.
        
           | qalmakka wrote:
           | NAT is arguably a very broken solution.IPv4 isn't meant to be
           | doing address translation, period. NAT creates all sorts of
           | issues because in the end you're still pretending all
           | communications are end to end, just with a proxy. We had to
           | invent STUN and all sorts of hole punching techniques just to
           | make things work decently, but they are lacking and have lots
           | of issues we can't fix without changing IPv4. I do see why
           | some people may like it, but it isn't a security measure and
           | there are like a billion different ways to have better, more
           | reliable security with IPv6. The "I don't want my devices to
           | have public, discoverable IPs" is moot when you have
           | literally billions of addresses assigned to you. with the /48
           | your ISP is supposed to assign you you may have 4 billion
           | devices connected, each one with a set of 281 trillion unique
           | addresses. You could randomly pick an IP per TCP/UDP
           | connection and not exhaust them in _centuries_. The whole
           | argument is kind of moot IMHO, we have ways to do privacy on
           | top of IPv6 that don't require fucking up your network stack
           | and having rendezvous servers setting that up.
           | 
           | We may also argue that NAT basically forces you to rely on
           | cloud services - even doing a basic peer to peer VoIP call is
           | a poor experience as soon as you have 2 layers of NAT. We had
           | to move to centralised services because IPv4 made hosting
           | your own content extremely hard, causing little interest in
           | symmetrical DSL/fiber, leading to less interest into ensuring
           | peer to peer connections between consumers are fast enough,
           | which lead to the rise of cloud and so on. I truly believe
           | that the Internet would be way different today if people
           | could just access their computers from anywhere back in the
           | '00s without having to know networking
        
             | zekica wrote:
             | And the worst part about CGNAT is that you have two bad
             | solutions:
             | 
             | Either EIM/EIF (preferably with hairpinning) where you can
             | practically do direct connections but you have to limit
             | users to a really low number of "connections" breaking
             | power users.
             | 
             | Or EDM/EDF where users have a higher number of
             | "connections" but it's completely impossible to do direct
             | connections (at least not in any video/voice calling
             | system).
        
           | Sanzig wrote:
           | Why don't you want every device to have a public IP? There
           | seems to be a perception that this is somehow insecure, but
           | the default configuration of any router is to firewall
           | everything. And one small bonus of the huge size of a /64 is
           | that port scanning is not feasible, unlike in the old days
           | when you could trivially scan a whole IPv4 /24 of a company
           | that forgot to configure their firewall.
           | 
           | NAT may work fine for your setup, but it can be a _huge_
           | headache for some users, especially users on CGNAT. How many
           | years of human effort have gone towards unnecessary NAT
           | workarounds? With IPv6, if you want a peer-to-peer connection
           | between firewalled peers, you do a quick UDP hole punch and
           | you 're done - since everything has a unique IP, you don't
           | even need to worry about remapping port numbers.
           | 
           | Your ISP shouldn't be rotating your /64, although
           | unfortunately many do since they are still IPv4-brained when
           | it comes to prefix assignment. Best practice is to assign a
           | static /56 per customer, although admittedly this isn't
           | always followed.
           | 
           | And if you don't need a /48... don't use it? 99.99% of home
           | customers will just automatically use the first /64 in the
           | block, and that's totally fine. There's a ton of address
           | space available, there's no drawback to giving every customer
           | a /56 or even a /48.
        
             | iamnothere wrote:
             | I don't want some of my devices to be publicly addressable
             | at all, even if I mess up something at the firewall while
             | updating the rules. NAT provides this by default.
             | 
             | I don't want a static address either (although static
             | addresses should be freely available to those who want
             | them). Having a rotating IP provides a small privacy
             | benefit. People who have upset other people during an
             | online gaming session will understand; revenge DDoS is not
             | unheard of in the gaming world.
        
               | ac29 wrote:
               | > I don't want some of my devices to be publicly
               | addressable at all, even if I mess up something at the
               | firewall while updating the rules. NAT provides this by
               | default.
               | 
               | This feels like a strawman. If you are making the sort of
               | change that accidentally disables your IPv6 firewall
               | completely, you could accidentally make a change that
               | exposed IPv4 devices as well (accidentally enabling DMZ,
               | or setting up port forwarding incorrectly for example).
        
               | iamnothere wrote:
               | As someone who has done this while tired, it's a lot
               | easier to accidentally open extra ports to a publicly
               | routable IP (or overbroad range of IPs) than it is to
               | accidentally enable port forwarding or DMZ.
        
               | wredcoll wrote:
               | You could accidentally swap ips to one that had a port
               | forward, some applications can ask routers to forward,
               | etc etc. I donmt know how exactly we'd measure the
               | various potential issues but they seem incredibly minor
               | compared to the sheer amount of breakage created by
               | widespread nat.
        
               | iamnothere wrote:
               | I don't have any problems with NAT on my network.
        
               | UltraSane wrote:
               | You can have IPv6 firewalls emulate the behavior of NAT
               | so it blocks unsolicited inbound traffic while allowing
               | outbound traffic. If you get a /48 form your ISP you
               | could rotate to a new IP address every second for the
               | rest of your life.
        
               | iamnothere wrote:
               | Right, but if you're messing around as a naive learner
               | it's easy to accidentally disable that or completely open
               | up an IP or range due to a bad rule. It's a lot harder to
               | accidentally enable port forwarding on a NAT.
        
               | degamad wrote:
               | > It's a lot harder to accidentally enable port
               | forwarding on a NAT.
               | 
               | It's probably less than three clicks on most home router
               | web UIs.
        
               | iamnothere wrote:
               | Very hard to make all those clicks accidentally. But
               | anyway I'm talking about pf/iptables rules, not web UIs.
        
               | MisterTea wrote:
               | But you have to specify not only the exposed port but
               | also the destination address and port which is not easy
               | to do accidentally.
               | 
               | edit: typo
        
               | throw0101c wrote:
               | > _You can have IPv6 firewalls emulate the behavior of
               | NAT so it blocks unsolicited inbound traffic while
               | allowing outbound traffic._
               | 
               | Are there any (consumer?) firewalls that do _not_ do
               | this? I know Asus do this (and have for years).
               | 
               | AIUI most 'enterprise' firewalls have a _default deny_
               | shipped from the factory and you have to actively allow
               | stuff.
        
               | craftkiller wrote:
               | > I don't want some of my devices to be publicly
               | addressable at all, even if I mess up something at the
               | firewall while updating the rules. NAT provides this by
               | default.
               | 
               | Do you ever connect your laptop to any network other than
               | your home network? For example, public wifi hotspots,
               | hotel wifi, tech conferences, etc? If so, you need to be
               | running a firewall _on your laptop_ anyway because your
               | router is no longer there to save you from the other
               | people on that network.
               | 
               | It's also a good idea even inside your home network,
               | because one compromised device on your network could then
               | lead to all your other firewall-less devices being
               | exploited.
        
               | iamnothere wrote:
               | Not every device can run its own firewall. IoT devices,
               | NVR systems, etc should be cordoned off from the internet
               | but typically cannot run their own firewall.
        
               | iso1631 wrote:
               | Sure, but they sit on an iot vlan where your firewall
               | prevents access except specificly allowed services
        
               | iamnothere wrote:
               | You must have not read my original post. I said that the
               | NAT provides an additional fallback layer of safety in
               | case you accidentally misconfigure your firewall. (This
               | has happened to me once before while working late and
               | I've also seen it in the field.)
        
               | icedchai wrote:
               | Most public wifi has client isolation enabled for this
               | reason. Firewall or not, you can't communicate with other
               | clients.
        
             | everdrive wrote:
             | > hollowing can crash the target process if the payload
             | isn't carefully matched to the host process architecture.
             | 
             | So here's the thing. My ISP does _not_ rotate my IPv4
             | address, but _does_ rotate IPv6. Why? I'll never know.
             | 
             | Anyhow. I'm not confused about NAT vs. firewalling. No one
             | who dislikes IPv6 is confused by this.
        
               | throw0101c wrote:
               | > _Anyhow. I 'm not confused about NAT vs. firewalling.
               | No one who dislikes IPv6 is confused by this._
               | 
               | "No one"; LOL. I've participated in entire sub-threads on
               | HN with people insisting that NAT = security. I've cited
               | well-regarded network educators/commentators and vendors:
               | 
               | * https://blog.ipspace.net/2011/12/is-nat-security-
               | feature/
               | 
               | * https://www.f5.com/resources/white-papers/the-myth-of-
               | networ...
        
               | aeonik wrote:
               | That article is making a narrower claim than you're
               | implying. It argues that NAT is not a security mechanism
               | by design and that some forms of NAT provide no
               | protection, which is true.
               | 
               | It also explicitly acknowledges that NAT has side effects
               | that resemble security mechanisms.
               | 
               | In typical deployments, those side effects mean internal
               | hosts are not directly addressable from the public
               | internet unless a mapping already exists. That reduces
               | externally reachable attack surface.
               | 
               | So, the disagreement here is mostly semantic. NAT is not
               | a security control in the design sense, but it does have
               | security-relevant effects in practice.
               | 
               | I personally do consider NAT as part of a security
               | strategy. It's sometimes nice to have.
        
             | jrm4 wrote:
             | Great question and my gut is that it makes it _that much
             | easier_ for large, perhaps corporate interests to gain
             | surveillance and control. I 'm aware it's possible now, but
             | it really feels like there's some safety in the friction of
             | the possibility that my home devices just switch up IP
             | addresses once in a while.
             | 
             | Like, wouldn't e.g. IPv6 theoretically make "ISP's charging
             | per device in your home" easier, if only a little bit? I
             | know they COULD just do MAC addresses, but still.
        
               | craftkiller wrote:
               | You can't correlate the number of addresses with the
               | number of devices because IPv6 temporary addresses exist.
               | If you enable temporary addresses, your computer will
               | periodically randomly generate a new address and switch
               | to it.
               | 
               | https://www.rfc-editor.org/rfc/rfc8981.html
        
               | jrm4 wrote:
               | "If you enable" is doing ALL THE HEAVY LIFTING THERE.
               | 
               | Again, my point isn't about what is possible, but what is
               | _likely._ -- which is MUCH MORE IMPORTANT for the real
               | world.
               | 
               | If we'd started out in an IPv6 world, the defaults would
               | have been "easy to discover unique addresses" and it's
               | reasonable to think that would have made "pay per device"
               | or other negatives that much easier.
        
               | craftkiller wrote:
               | Temporary addresses are enabled by default in OSX,
               | windows, android, and iOS. That's what, like 95% of the
               | consumer non-server market? As for Linux, that's going to
               | be up to each distro to decide what their defaults are.
               | It looks like they are _not_ the default on FreeBSD,
               | which makes sense because that OS is primarily targeting
               | servers (even though I use it on my laptop).
        
               | zekica wrote:
               | Temporary addresses are used by any Linux distro using
               | NetworkManager (all desktop ones). For server distros, it
               | can differ.
        
               | Levitating wrote:
               | In Gnome it's just a toggle in the network settings
        
               | electronsoup wrote:
               | and most OS do enable it by default
        
               | password4321 wrote:
               | > _ALL THE HEAVY LIFTING THERE_
               | 
               | > _MUCH MORE IMPORTANT_
               | 
               | I haven't done the exhaustive research but props in
               | advance for being the only person shouting in caps on HN.
               | Definitely one way to proclaim one's not AI-ness without
               | forced spelling errors.
        
               | saltcured wrote:
               | I feel like this is a silly narrowing of the problem for
               | normal, retail users. My priority isn't masking "the
               | number of addresses" or devices. My desire is to not have
               | a persistent identifier to correlate all my traffic. The
               | whole idea of temporary addresses fails at this because
               | the network prefix becomes the correlation ID.
               | 
               | I'm not an IPv4 apologist though. Clearly the NAT/DHCP
               | assignments from the ISP are essentially the same risk,
               | with just one shallow layer of pseudo-obscurity. I'd
               | rather have IPv6 and remind myself that my traffic is
               | tagged with my customer ID, one way or another.
               | 
               | Unfortunately, I see no real hope that this will ever be
               | mitigated. Incentives are not aligned for any ISP to
               | actually help mask customer traffic. It seems that onion
               | routing (i.e. Tor) is the best anyone has come up with,
               | and I suspect that in today's world, this has become a
               | net liability for a mundane, privacy-conscious user.
        
               | ronsor wrote:
               | > The whole idea of temporary addresses fails at this
               | because the network prefix becomes the correlation ID.
               | 
               | So the same as the public IPv4 on a traditional home NAT
               | setup?
        
               | graemep wrote:
               | Most home users do not have a static public IPv4 address
               | - they have a single address that changes over time.
        
               | db48x wrote:
               | But most ISPs aren't giving out static IPv6 prefixes
               | either. Instead they are collecting logs of what
               | addresses they've handed out to which customer and
               | holding on to them for years and years in case a court
               | requests them. Tracking visitors doesn't need to use ip
               | addresses simply because it's trivial to do so with
               | cookies or browser fingerprinting. There's exactly zero
               | privacy either way.
        
               | throw0101c wrote:
               | > _Most home users do not have a static public IPv4
               | address - they have a single address that changes over
               | time._
               | 
               | I'd be curious to know the statistics on this: I would
               | hazard to guess that for most ISPs, if your router/modem
               | does not reboot, your IPv4 address (and IPv6 prefix) will
               | not change.
        
               | throw0101c wrote:
               | > _My desire is to not have a persistent identifier to
               | correlate all my traffic._
               | 
               | Reboot your router. Asus (with the vendor firmware)
               | allows you do this in a scheduled manner. You'll get a
               | new IPv4 WAN IP (for your NAT stuff) and (with most ISPs)
               | a new IPV6 prefix.
               | 
               | As it stands, if you think NAT hides an individual
               | device, you may have a false sense of security (PDF):
               | 
               | * https://oasis.library.unlv.edu/cgi/viewcontent.cgi?arti
               | cle=1...
        
             | zadikian wrote:
             | Many routers don't firewall by default. Lemme check later,
             | but pretty sure my basic ASUS router doesn't either.
        
             | ErroneousBosh wrote:
             | > Why don't you want every device to have a public IP?
             | 
             | What would be the advantage in it?
        
               | zekica wrote:
               | Trivially easy do direct connections between devices (if
               | desired), no issues when creating VPNs between networks
               | using private ranges.
               | 
               | What would be the disadvantage?
        
               | ErroneousBosh wrote:
               | Well, the disadvantage would be that it would be really
               | difficult to do direct connections between devices.
               | 
               | I don't want VPNs between private ranges.
               | 
               | I don't want publically-routable IP addresses on
               | _anything_.
        
               | throw0101c wrote:
               | >> Why don't you want every device to have a public IP?
               | 
               | > What would be the advantage in it?
               | 
               | Not having to deal with ICE/TURN/STUN. Being able to
               | develop P2P applications without having to build out that
               | infrastructure (anyone remember Skype's "supernodes"?).
        
             | donmcronald wrote:
             | > Why don't you want every device to have a public IP?
             | 
             | Big companies would abuse that beyond belief. Back around
             | the late 90s ISPs wanted to have everyone pay per device on
             | their local networks. NAT was part of what saved us from
             | that.
             | 
             | IMO, IPv6 should have given more consideration to the
             | notation. Sure, hex is "better in every way" _except_ when
             | people need to use it. If we could just send the IPv6
             | designers back in time, they could have made everyone use
             | integer addresses.                   # IPv4 - you can ping
             | this         ping 16843009         # IPv6 - if they hadn't
             | broke it :-(         ping
             | 50129923160737025685877875977879068433         # IPv7 -
             | what could have been :-(         ping 193103865318954629859
             | 13581418294584302690104794478241438464910045744047689
             | 
             | It's simple, unambiguous, and scales infinitely.
        
               | vel0city wrote:
               | > Back around the late 90s ISPs wanted to have everyone
               | pay per device on their local networks. NAT was part of
               | what saved us from that.
               | 
               | But with IPv6 a single device may have multiple
               | addresses, some of which it just changes randomly. So
               | this idea that they'll then know how many devices you
               | have and be able to pay per device isn't really feasible
               | in IPv6.
               | 
               | A single /64 being assigned to your home gives you over
               | 18 _quintillion_ addresses to choose from.
               | 
               | If the ISP really wanted to limit devices they'd rely on
               | only allowing their routers and looking at MAC addresses,
               | but even then one can just put whatever to route through
               | that and boom it's a single device on the ISP's lan.
        
               | NewJazz wrote:
               | _It 's simple, unambiguous, and scales infinitely_
               | 
               | This is a joke right? How does it "scale infinitely"? It
               | is clearly ambiguous in your ipv7 example.
        
             | cyberax wrote:
             | > Why don't you want every device to have a public IP?
             | 
             | Suddenly, your smart lightbulb is accessible by everyone.
             | Not a great idea.
             | 
             | > With IPv6, if you want a peer-to-peer connection between
             | firewalled peers, you do a quick UDP hole punch and you're
             | done - since everything has a unique IP, you don't even
             | need to worry about remapping port numbers.
             | 
             | There is no guarantee with IPv6 that hole punching works.
             | It _usually_ does like with IPv4.
        
               | Marsymars wrote:
               | > Suddenly, your smart lightbulb is accessible by
               | everyone. Not a great idea.
               | 
               | The answer here is kinda that Wi-Fi isn't an appropriate
               | networking protocol for lightbulbs (or most other devices
               | that aren't high-bandwidth) in the first place.
               | 
               | Smart devices that aren't high bandwidth (i.e. basically
               | anything other than cameras) and that don't need to be
               | internet accessible outside of a smart home controller
               | should be using one of Z-Wave/Zigbee/Thread/LoRaWAN
               | depending on requirements, but basically never Wi-Fi.
        
               | zadikian wrote:
               | Silliness of smart bulbs aside, I would hope the answer
               | is how ipv6 is actually safe for this, not that you
               | should just not use wifi.
        
               | Marsymars wrote:
               | Well Thread uses ipv6 in a safe way for this, nobody ever
               | complains about how they wish their Thread network only
               | used ipv4. :)
        
               | Aluminum0643 wrote:
               | > Suddenly, your smart lightbulb is accessible by
               | everyone.
               | 
               | A firewall solves that issue, IPv4 or IPv6.
        
               | ryandrake wrote:
               | A lot of people, even on HN, mistake "addressable" for
               | "accessible".
        
               | XorNot wrote:
               | It's because router defaults have been bad for a long
               | time and NAT accidentally made them better.
               | 
               | I finally have IPv6 at home but I am being very cautious
               | about enabling it because I don't really know what the
               | implications are, and I do not trust the defaults.
        
               | throw0101c wrote:
               | >> Why don't you want every device to have a public IP?
               | 
               | > Suddenly, your smart lightbulb is accessible by
               | everyone. Not a great idea.
               | 
               | Why would it be "accessible by everyone"? My last ISP had
               | IPv6 and my Asus (with the vendor firmware) didn't allow
               | it. My printer automatically picked up an IPV6 address
               | via SLACC and it was not "accessible by everyone" (I
               | tried connecting to it externally).
        
             | iso1631 wrote:
             | My ISP doesn't rotate my /48
             | 
             | However if I change my ISP I get a new one, and that means
             | a renumbering.
        
           | knorker wrote:
           | So run fc00::/7 addresses with IPv6 NAT.
           | 
           | That addresses all of your concerns, and you have that
           | option.
        
             | justsomehnguy wrote:
             | But that doesn't allow to bitch about it so - no.
        
             | iso1631 wrote:
             | Sure you can do that
             | 
             | So what's the point in ipv6?
        
               | zekica wrote:
               | You can do fc00::/7 in addition to public addresses so
               | your lights don't have public address while your phone
               | does.
        
               | knorker wrote:
               | I mean, so many reasons. Not the least of which is
               | carrier grade NAT is out. And that alone implies so much
               | cost savings, performance increase, and home user
               | flexibility .
               | 
               | I'm struggling to assume good faith on your question,
               | since it's so strange. I feel like I need to start from
               | scratch explaining the internet, since asking this
               | question reveals a lack of knowledge about everything
               | networking.
        
           | UltraSane wrote:
           | NAT is a horrible, HORRIBLE hack that makes everything in
           | networking much more complicated. IP networking is very
           | elegant when everyone is using globally unique addresses and
           | a ugly mess when Carrier NAT is used.
        
           | bigstrat2003 wrote:
           | NAT demonstrably does not work fine. We have piles of ugly
           | hacks (STUN, etc) that exist only because NAT does. If you
           | really want to keep NAT then nothing stops you from running
           | it on IPv6, but the rest of us shouldn't suffer because of
           | your network design goals.
        
           | blueflow wrote:
           | > I like NAT
           | 
           | I'm in favor of having society overrule you. NAT is a
           | horrible kludge and not okay. Never was.
        
           | throwaway27448 wrote:
           | How is a public address any worse than NAT? You can always
           | choose to not respond.
        
         | sidewndr46 wrote:
         | Why, so you can inflict some personal pain on people without
         | IPv6 access?
        
           | lxgr wrote:
           | Surely IPv6 support will spontaneously materialize on their
           | networks once their pain becomes big enough!
        
           | miyuru wrote:
           | I am running IPv6 only servers, and I think it's fair that v4
           | only people feel the same pain some time in the future.
        
             | traderj0e wrote:
             | IPv6: only better than v4 if you kneecap v4, even then
             | maybe not
        
         | kevvok wrote:
         | It's not implemented in the Linux kernel, but the latency
         | penalty you're describing is part of the "Happy Eyeballs"
         | algorithm: https://en.wikipedia.org/wiki/Happy_Eyeballs
        
         | apitman wrote:
         | As sad as it makes me to admit, I don't think IPv6 is ever
         | going to happen without government intervention. Adoption is
         | flat at under 50% over the past year. IPv6 doesn't benefit big
         | tech. SNI routing and NAT work pretty well for centralized
         | platforms. AWS will gladly rent us IPv4 addresses until the end
         | of time.
        
           | toast0 wrote:
           | > IPv6 doesn't benefit big tech.
           | 
           | It does, and big tech has largely adopted IPv6.
           | 
           | For users with IPv6, the v6 path is often less constrained
           | than then v4 path. Serving data faster/more consistently is
           | of benefit to big tech. For a lot of users, v4 and v6 routing
           | are different, which is also helpful for big tech. If you
           | have two paths to the server (and happy eyeballs or
           | something), you have more resiliance to routing issues.
           | 
           | Clouds are slow on v6, but CDNs are not. Adoption on eyeball
           | networks has been _very_ slow, and it 's unlikely to speed up
           | much, IMHO. The benefits of v6 for ISPs are not that big for
           | established serviced with large v4 pools. For ISPs running
           | CGNAT, more v6 means less CGNAT and CGNAT is a lot more
           | expensive than plain ip routing. (Doesn't mean all CGNAT
           | providers run v6, but it's an incentive).
        
           | zekica wrote:
           | SNI routing is such a bad way to do what should be L3 problem
           | that people implemented PROXY protocol to send information
           | about user's endpoint address without doing MITM.
        
           | Dagger2 wrote:
           | The Internet itself is growing, so "50%" does still represent
           | a growing number of users. Also Google's stats are missing
           | half a billion v6 users from China.
        
           | traderj0e wrote:
           | Another way to do ipv6 without government intervention is to
           | make it 1. actually what people want, just v4 with more bits
           | 2. have a reasonable migration path from v4. They made
           | something overcomplicated that disregards all existing users,
           | and now they act like this was the only possible way to avoid
           | address exhaustion and it's everyone's obligation to switch.
           | Even if the govt successfully forced v6, it'd be a downgrade.
        
         | nurettin wrote:
         | > enjoy if there was a manually induced latency penalty for
         | "legacy IP" that needs to be manually turned off on Linux
         | 
         | That sounds so bad, it probably will be a windows feature.
        
         | hrmtst93837 wrote:
         | Making IPv4 intentionally laggy would break orgs that depend on
         | ancient gear or SaaS with hardwired v4, for a purist's thrill
         | and outages for users.
        
       | petcat wrote:
       | It will be a neat experiment, but I think most software will
       | break and will remain broken indefinitely and then people will
       | turn to LLMs to try to automate fixing all of it and that will
       | turn into a mess just due to the sheer amount of changes required
       | with little scrutiny.
        
         | gear54rus wrote:
         | Perhaps it's time to submit patches that allow building it
         | without IPv6 instead. Countless hours of configuration meddling
         | will be saved.
        
           | zamadatix wrote:
           | Not sure if you're taking the piss or just missed it but
           | allowing build with either protocol alone is one of the
           | genuine ideas in this joke:
           | 
           | > Yeah. The date notwithstanding, I do actually think we
           | should do most of this for real.
           | 
           | > Maybe we don't get away with the actual deprecation and the
           | warnings on use _just_ yet, and _maybe_ we won 't even get
           | away with calling the config option CONFIG_LEGACY_IP,
           | although I would genuinely like to see us moving consistently
           | towards saying "Legacy IP" instead of "IPv4" everywhere.
           | 
           | > But we _should_ clean up the separation of CONFIG_INET and
           | CONFIG_IPV[64] and make it possible to build with either
           | protocol alone.
        
       | Daegalus wrote:
       | great, now can we convince the rest of the internet to start
       | adding AAAA records and ipv6 endpoints for things. Github is
       | still a nightmare to use DNS64 and NAT64 to access those from
       | IPv6 only machines.
       | 
       | Or all the Container based stuff that still falls flat with ipv6
       | only modes. Docker still shits the bed if you dont give it ipv4
       | unless you do a lot of manual overrides to things. A bunch of
       | Envoy based gateway proxies fail on internal ipv6 resources in a
       | k8s cluster that runs on ARM64.
       | 
       | There is just a bunch of nonsense you have to deal with if you
       | choose the ipv6-only route
       | 
       | Dont get me started on CDNs like Bunny or Load Balancers as a
       | service like those from Hetzner, UpCloud, etc that don't work
       | with ipv6 origins.
       | 
       | Source: Trying to run a ipv6 only self-hosted box on hetzner.
        
         | mhitza wrote:
         | I've tried to run an IPv6 only box on Hetzner 2-3 years ago.
         | Didn't have a problem with the platform, but with RedHat
         | because subscription-manager didn't work over a IPv6-only
         | stack.
        
           | tialaramex wrote:
           | When I accidentally had IPv6 only for a new Windows box it
           | was very apparent what was a priority (worked regardless) and
           | what wasn't important (only began working once I had IPv4 and
           | everything fixed too).
           | 
           | Baked in advertising? Works with any network. The option to
           | _turn off_ the baked in advertising? That needs IPv4.
        
           | PennRobotics wrote:
           | Around the same time, I think the Photoprism image also
           | didn't work on IPv6 because of Traefik
        
         | Macha wrote:
         | I honestly think GitHub and AWS are the two biggest blockers to
         | IPv6 left. Sure your public web servers might need IPv4 for a
         | long while yet, but all these backend microservices and CI
         | builds etc could all be v6 only, except they need to pull stuff
         | from GitHub or certain AWS services.
        
           | Sanzig wrote:
           | It's particularly aggravating with AWS, since they charge for
           | IPv4 addresses yet many of their services aren't IPv6
           | capable.
        
       | CookieCrisp wrote:
       | We're so close guys! Another 25 years and we might almost be
       | there!
        
       | porridgeraisin wrote:
       | I suppose this will lead to a classic torvalds rant. I will be
       | watching r/linusrants
        
       | zamadatix wrote:
       | Good stuff (both the joke and the genuine proposal of splitting
       | the config options for IPv4 and IPv6).
        
       | bornfreddy wrote:
       | IPv6 vs. 4 is like Python 3 vs. 2, just worse.
        
         | lxgr wrote:
         | And IPv6 vs v4 discussions are just like Python 3 vs. 2
         | discussions: Often much more annoying than just getting it over
         | with and switching.
        
           | patmorgan23 wrote:
           | This. Sure there are still some applications that might be
           | difficult to v6 enable, so either patch it or use one of the
           | myriad of options to give it a v6 front end.
        
           | zadikian wrote:
           | It would've been less annoying to not do a breaking change
           | from Py2 to 3. JS never had a breaking change like that.
        
         | craftkiller wrote:
         | There are genuine improvements in IPv6 aside from the abundance
         | of addresses. The two that immediately come to my mind are:
         | 
         | 1. SLAAC means routers no longer need to keep a record of each
         | client on the network. With DHCP, the router had to maintain a
         | table of which addresses had been assigned and getting an
         | address involved 2-way communication. With SLAAC the router
         | just periodically broadcasts the prefix to the network and any
         | device that wants an address can just listen to that broadcast
         | and assign themselves an address within that prefix without
         | having to inform the router and without the router needing to
         | maintain a table of assigned addresses. (2-way communication is
         | still possible since devices can solicit a broadcast but it is
         | not necessary)
         | 
         | 2. With IPv6, middleboxes are no longer allowed to fragment
         | packets. The only device that can fragment a packet is the
         | original sender. If any segment along the path has a lower MTU
         | than the size of the packet, the original sender is notified
         | and then they can fragment the packet.
        
       | 1970-01-01 wrote:
       | The best pranks are the ones that succeed to rattle an
       | individual. Build it!
        
       | ThrowawayTestr wrote:
       | When I was in grade school I did a presentation on ipv6 and how
       | it was the future of the Internet. That was like 20 years ago.
        
       | iamnothere wrote:
       | This may be a "joke", but it's disturbing to see people clamoring
       | to deny others their freedom in a FOSS context.
       | 
       | Want to use IPv6? Fine. But don't try to remove v4 support from
       | people who have built stable networks around it.
       | 
       | You won't be able to force the world to switch to IPv6 with
       | tricks like this, any more than you can force old industrial
       | machines to stop using ancient 486es as controllers. There is a
       | lot of old equipment in the world.
       | 
       | IPv6 was built to work alongside v4, and there is no reason to
       | change that.
        
         | embedding-shape wrote:
         | > it's disturbing to see people clamoring to deny others their
         | freedom in a FOSS context
         | 
         | How does "allow building Linux to be IPv6-only" somehow "deny
         | others their freedom" exactly? I'm willing to wager most
         | distributions will still be dual v4+v6, but if they aren't,
         | isn't that something for you to bring up with your distribution
         | rather than that the kernel just allows something?
        
           | iamnothere wrote:
           | Coupling this patch with language about "legacy IP", along
           | with the follow up comments from the person who submitted the
           | patch, it is clear that the submitter is hostile towards
           | IPv4. I also see hostility towards IPv4 in the comments here
           | and other similar discussions.
           | 
           | I have no problem with allowing optional IPv4 or IPv6 only
           | builds as long as both are kept well-maintained.
        
             | embedding-shape wrote:
             | > it is clear that the submitter is hostile towards IPv4
             | 
             | But so what? It still doesn't remove v4, in any shape or
             | form, and if that was proposed to the kernel, I'm again
             | fairly confident it'd be rejected.
             | 
             | > I also see hostility towards IPv4 in the comments here
             | and other similar discussions
             | 
             | Ah, yeah that might be. I just saw your comment first, with
             | no context of what you were actually answering, so it kind
             | of looks like you're replying "to the submission", which
             | really isn't denying any freedoms, I guess I was confused
             | about that, my bad. Still, wouldn't it be better to answer
             | directly to those comments, rather than "replying" to an
             | argument/debate that is actually happening elsewhere?
        
               | iamnothere wrote:
               | Somehow IPv4 versus IPv6 has become one of those noxious
               | political-technical debates like Android versus Apple or
               | GPL versus BSD/MIT, in which both sides are dug in and
               | think that the other side must be destroyed.
               | 
               | The reason that I don't like seeing patches like this,
               | even as a "joke", is that there are real people who would
               | like to see IPv4 removed (possibly by government
               | intervention) in order to achieve their dream of an IPv6
               | only internet. The whole idea is preposterous, but here
               | we are. It's about as realistic as banning cars but that
               | doesn't stop the endless flame wars about it.
               | 
               | Someone has to step in to point out that v4 and v6 were
               | designed to coexist, this is fine, please don't remove
               | common standards for your personal preferences.
        
         | budman1 wrote:
         | *removed comment. I didn't know this was an April fools joke.
         | sorry for my lack of a clue....
        
           | zamadatix wrote:
           | The patchset is an April fools joke and even then it's not
           | going this far.
        
         | bladeee wrote:
         | What? Freedom to opt in or out is good either way.
        
         | traderj0e wrote:
         | v6 was meant to succeed v4, not work alongside it.
         | https://datatracker.ietf.org/doc/html/rfc8200#section-1
        
       | knorker wrote:
       | I would like this option, to make it easier to run a CI
       | environment truly IPv6-only. As in socket() to create a v4 socket
       | should fail.
       | 
       | seccomp could only do this partially, in that there are other
       | avenues (e.g. io_uring), and I want it to be the case throughout
       | the boot process.
        
         | iso1631 wrote:
         | Creating a v4 socket should map to a v6 address lower down,
         | making v6 transparent to v4 only applications.
        
       | Incipient wrote:
       | The main thing I don't like is type-ability. Even now I type in
       | 192.168.1.14 to connect to my mates computer to play
       | satisfactory. No way in heck am I trying in an ip6!
        
         | patmorgan23 wrote:
         | Hmmmm maybe someone should come up with a SYSTEM to organize
         | NAMES for ips, maybe using hierarchical DOMAINs.... Oh wait.
        
           | gertop wrote:
           | Your bad attempt at humor makes it quite clear that you've
           | never dealt with network engineering or administrating to any
           | extent.
           | 
           | Admitting that ipv6 has some downsides, however minor they
           | may seem to you, won't hurt your quest to render ipv4
           | obsolete.
           | 
           | In fact being less insufferable is how you win people to your
           | causes, not by laughing at their genuine albeit minor issues.
        
             | fasterik wrote:
             | They were making a legitimate point a humorous way. The
             | problem of manually typing in IP addresses has been solved
             | by DNS for over 50 years.
        
               | ryandrake wrote:
               | I haven't had to type an IP address to access something
               | on my home network for at least a decade, except for
               | (occasionally) my xxx.1 router.
        
           | matthews3 wrote:
           | We could abbreviate that to SND!
        
         | bpavuk wrote:
         | how about just having zeroconf on and using .local domains?
        
         | vel0city wrote:
         | Why not just type in "mates-pc" and have functional mDNS and
         | not have to memorize a bunch of numbers?
         | 
         | Why not just expect your OS's DNS setup to actually just work?
        
           | IshKebab wrote:
           | Because mDNS usually doesn't work and just expecting it to
           | work doesn't change that?
        
             | vel0city wrote:
             | > Why not just expect your OS's DNS setup to actually just
             | work?
             | 
             | Maybe use an OS or DNS stack that isn't terrible?
             | 
             | Incredible asking for a not-broken DNS and IP stack is just
             | too far out there when it seems most of the closed source
             | OS platforms seem to manage just fine.
             | 
             | Or let me guess, you've specifically configured it to not
             | "leak" such useful information?
        
             | guntars wrote:
             | Skill issue. Works fine for me in a mixed Linux/Apple
             | environment.
        
               | IshKebab wrote:
               | I didn't write any mDNS software. Blame those guys.
        
               | guntars wrote:
               | Well I mean "those guys" did a good job and the network
               | administrator might need to do some debugging.
        
               | zadikian wrote:
               | I never have to debug why my dhcp server isn't handing
               | out ipv4 addresses or deal with conflicts, but if I did,
               | it'd break mdns too. mdns is an extra moving part to deal
               | with.
        
               | vel0city wrote:
               | I've had numerous issues with dhcp servers over the years
               | and clients not understanding their responses. Acting
               | like they never have issues is just burying your head in
               | the sand. mDNS often works just fine on most common OSes,
               | if you don't explicitly block them.
        
               | guntars wrote:
               | By debugging I mean just checking if you have not blocked
               | broadcast packets at the firewall or some similar
               | misconfiguration. I doubt it's actual bugs when it
               | doesn't work. On your second point, it's actually more
               | resilient than DHCP because it works with IPv6 too.
        
               | IshKebab wrote:
               | What network administrator?
        
         | Dylan16807 wrote:
         | No way in heck are you typing fd00::d or similar? Why not?
        
         | password4321 wrote:
         | I recently learned I can skip middle .0's in IPv4, no more
         | 192.168's for me it's 10[.0.0]'s going forward.
        
       ___________________________________________________________________
       (page generated 2026-04-01 23:01 UTC)