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I spent a week without IPv4 to understand IPv6 transition mechanisms

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Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#481

Earlier quoted context omitted.

In any case, your endpoints really do need to be reasonably secure in themselves - especially if the firewall isn’t yours as then you are probably sharing the network with other devices on the inside of the network that can attack you directly, and even if not, it just takes one device being compromised and somebody has full inside access to the network, with the firewall not being able to do much…

Good luck with your home automation, printer, and tv

NAT doesn't protect you from things inside your LAN either. Where you have NAT+firewall with IPv4 now, you'll need a firewall with IPv6.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#482
post #402

Earlier quoted context omitted.

With the home router+wifi market estimated to be USD 2070.43 million in 2022, I wouldn't say it's a tiny percentage of people, just people you know.

1. Where does this stat come from? 2. You can't say anything about the percentage with just the absolute market value. At the very least you need something else to compare it too. Please, be serious.

A reader who's actually interested in getting the source, might try Googling for "2070.43", or even "2070.43 million wifi". I must admit, I wasn't serious enough about my comment to spend $3,250 on the whole report, and had to go off of the public preview. Since you seem to be more serious, maybe you could pay the $4,400 for a multi-user licensed copy of the report and share the PDF with me? I'd love to read more of the analysis.

So, I mean, I dunno, 2 billion dollars seems serious to me, but maybe we just have different barometers for what counts as "serious amounts of money". Especially considering these devices that are like $300.

Finally, might I remind you of the guidelines? in particular:

> When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3."

https://news.ycombinator.com/newsguidelines.html

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#483

Earlier quoted context omitted.

No idea. I've tried every setting combination on this consumer grade D-Link router which is supposed to support IPv6. Nothing results in a functioning network. Forum posts I find from other customers of this ISP report the same behaviour on other routers. The modem gets a /56 at least, and hands out addresses from a /64 range under that I assume, the router gets a /128 from the modem, and then gives up entirely on do…

It sounds like your ISP is delegating a prefix, then? Weird, that all sounds reasonable to me. What do you mean the router gives up entirely, though? Computers in the LAN don't get an IP address? Packets go out but nothing comes back?

Yup, computers on the LAN don't get any address. From what I understand, the modem would be supposed to delegate a prefix to the router so it can hand out addresses, but this part isn't happening.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#484
post #393

My experience with IPv6 is that routing generally goes faster and the network breaks down less. The statelessness of it all just makes it work. The fight between your average video game and NAT has caused me so many problems over the years (including port forwards to receive traffic because whatever NAT punching mechanism the game used didn't work). Running dual stack does cause some weird debugging ("why can't my la…

I agree, IPv4 has its problems. That is why we transition to IPv6. Dual Stack doesn't "solve" anything. You still run IPv4. With all the downsides, especially every machine will still need an (RFC 1918) IPv4 address. (Microsoft is running out of their internal 10.0.0.0/8: https://www.arin.net/blog/2019/04/03/microsoft-works-toward-... ) The goal of the IPv6 transition is to disable IPv4. NAT64+DNS64 or 464XLAT allows…

I would love full transitions to be easy enough to work. DNS64 breaks DNSSEC without updates to the spec, so that's not going to fly for me today. A competent DNS configuration would fail to resolve my IPv4 domains at the very least (though all of my public domains have an AAAA record, obviously). The only solution is to do DNSSEC validation at the DNS64 level which in my opinion defeats the purpose of DNS security all together.

For internal networks, IPv6 seems like an obvious choice. If you already have company wide subnets, you may as well set up some ULAs/GUAs and use IPv6 internally. Full IPv6 may be better but people worry about adversaries mapping internal networks for some reason so NAT66 may be necessary to placate those fears.

The problems you still keep around by using some kind of dual stacking (DS-Lite being the cheapest) ensures compatibility with servers and entire countries that haven't even begun upgrading their networks yet. You incur the IPv4 penalty, for sure, but only towards services that don't have IPv6. This provides an incentive for the world to move on without breaking existing infrastructure entirely.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#485

Earlier quoted context omitted.

Every guide I see tells you to disable Upnp (or IGD, the part of UPNP that lets you open ports), for good reason. It's a protocol that just disables the security you thought you had before. The reason Xboxes need port forwarding in the first place is that IPv4 relies on NAT. The unreliability and unpredictability of NAT means remote devices won't know what ports to talk to or if those ports will even be mapped to the…

UPNP is just fine assuming a secure implementation (some of the early ones were awful, but that doesn't make the concept bad). It doesn't reduce security anywhere near like what is made out. If you already have a device on your network that is compromised and is able to do UPNP requests, then you have a much bigger problem (in a home setting). But IPv6 doesn't solve the problem at all if all incoming connections are…

libupnp/miniupnp seem to support IPv6 pinholes just fine through WANIPv6FirewallControl. I don't sell routers so I don't know how up to date the libraries on your average router firmware are (most likely "ancient") but this isn't a protocol problem. If you run firmware like OpenWRT you've had support for it for at least five years now.

Most consumer routers I've seen these days come with UPNP disabled by default, though.

For most P2P traffic (which includes a third party handshake server) you can probably skip port forwarding entirely; just send UDP packets both ways and the firewall will figure it out. For stateful protocols like TCP and friends (SCTP etc.) that's harder to accomplish this, that's where you need pinholing.

It's possible that your router simply doesn't support IPv6 pinholing but I think the more likely scenario for breakages is that client software doesn't bother implementing it.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#486
post #480

Earlier quoted context omitted.

You can't have the best features of the two - in the sense of interoperability - because they are different on a fundamental level: it's impossible for IPv4 nodes to talk to IPv6 nodes without understanding the much larger address space. There were proposals back in the day (early 90s) for IPng (IP Next Gen, as IPv6 was called back then) to be a hierarchical routing algorithm, that could have kept backwards compatibi…

42% of the internet uses v6, and rising. The economic incentives for ISPs absolutely exist, as v4 addresses become ever more expensive and the cost of CG-NAT deployments continue to climb.

> v4 addresses become ever more expensive and the cost of CG-NAT deployments continue to climb.

But IPv6 is not an alternative to CGNAT. If you don't provide either a routable IPv4 or CGNAT, your customers will ask their money back because their internet is broken. The fact that you provide IPv6 or not is completely irrelevant to the vast majority of consumers or businesses.

This here is the major failure of IPv6 design, confusing what "the internet as a whole and the ISP community" need, with the individual incentives that make a single ISP provide for those needs.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#487
post #393

Earlier quoted context omitted.

I agree, IPv4 has its problems. That is why we transition to IPv6. Dual Stack doesn't "solve" anything. You still run IPv4. With all the downsides, especially every machine will still need an (RFC 1918) IPv4 address. (Microsoft is running out of their internal 10.0.0.0/8: https://www.arin.net/blog/2019/04/03/microsoft-works-toward-... ) The goal of the IPv6 transition is to disable IPv4. NAT64+DNS64 or 464XLAT allows…

I would love full transitions to be easy enough to work. DNS64 breaks DNSSEC without updates to the spec, so that's not going to fly for me today. A competent DNS configuration would fail to resolve my IPv4 domains at the very least (though all of my public domains have an AAAA record, obviously). The only solution is to do DNSSEC validation at the DNS64 level which in my opinion defeats the purpose of DNS security a…

> DNS64 breaks DNSSEC

Yes, it does. While in theory you could "undo" the translation and verify against the re-synthesized A record, nobody is going to do that.

464XLAT shifts the "make an IPv6 address from an IPv4" to the CPE or even end device (Apple Devices are known to work well with 464XLAT). For this the device discovers the prefix, and if software wants to make an IPv4 connection, it sends it to the NAT64 using the prefix + IP. DNS64 would be no longer needed.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#488
post #470

Earlier quoted context omitted.

I don't even necessarily disagree with you, but your examples don't seem accurate. Regarding firewalls bring prone to accepting by default, either way the packet has to go through the CPU to be routed. I don't believe there's any inherent bias in the design. You could argue that routers that use a single switch and vlan isolate the wan port are inherently biased, though. Regarding local hostname resolution, there are…

The words "local" or "home" network with IPv6 are an illusion, this is what I wanted to show with my examples, Firstly one ceases to have control of its own home network, what now have to rely on the ISP for to receive the "local" IPs, what are part of internet. And in addition each machine leaves a trace of its "local" ip on the Internet. This if one want internet access in the device, due the absence of NAT in the…

I still don't think you're really providing any examples or arguments that make your point, though. You're just coming across as really salty about IPv6. I'm not downvoting you.

IPv6 has link-local addresses that aren't routable, so you can't really get more local than that. Unlike a typical IPv4 setup, typical IPv6 hosts have multiple addresses, and you can make your own for local traffic and only rely on ISP prefixes for internet access if you want to.

Sure, the internal host's internet routable IP address is visible rather than being masked behind the router's IP address. Pretty much all operating systems periodically randomize the bottom 64 bits, making it effectively as opaque as NAT. You could call that a hack, but people call NAT a hack. There's tradeoffs.

The CVE links you provided are just lists of vulnerabilities with "firewall" in the name. Skimming through them, I don't see how they're specific to IPv6? Most of the vulnerability descriptions I read seem equally problematic for NAT setups. The one IPv6 specific one I saw had to do with a bad firewall rule allowing access to LAN facing services running on the router; it could have just as easily been a bad IPv4 rule.

I agree, consumer network gear all sucks. IPv6 is bolted on as an afterthought, and is probably buggy in a lot of them. More features means more opportunity for bugs, but that's true of anything. IPv6 isn't being deployed for no reason; there's limited IPv4 addresses to go around. I still don't follow why IPv6 is fundamentally riskier than IPv4 when traversing a router. Sure, with NAT an incoming packet needs to have a port number that's been dynamically mapped back to an internal host and port, or have a static port forward. In IPv6, an incoming packet needs to have a destination address and port that's been dynamically mapped back to an internal host and port, or have a static firewall rule. It's basically the same, but also less complicated for the router because there's no translation involved. In time, less complexity is good for software hardness.

I also get anxiety from trying to wrap my head around IPv6 address assignment. It is nuts. It's very comforting to work in the effectively 8-bit address space of a /24 IPv4. I suppose it's true that you can't control internet routable IPv6 addresses in that they are dynamic and ephemeral in their nature. Coming from IPv4, it feels messy. I've experimented in detail with configuring my own ULA, DHCPv6 configuration, and SLAAC. I've tried to embrace the benefits of IPv6, and having used a few of the features I can appreciate them for what they are.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#489
post #470

Earlier quoted context omitted.

I don't even necessarily disagree with you, but your examples don't seem accurate. Regarding firewalls bring prone to accepting by default, either way the packet has to go through the CPU to be routed. I don't believe there's any inherent bias in the design. You could argue that routers that use a single switch and vlan isolate the wan port are inherently biased, though. Regarding local hostname resolution, there are…

The words "local" or "home" network with IPv6 are an illusion, this is what I wanted to show with my examples, Firstly one ceases to have control of its own home network, what now have to rely on the ISP for to receive the "local" IPs, what are part of internet. And in addition each machine leaves a trace of its "local" ip on the Internet. This if one want internet access in the device, due the absence of NAT in the…

Not at all, your "local" network is the link-local address space, which legacy IP has no analog of. The link-local space cannot be routed either intentionally or accidentally.

RFC1918 address space IS routable, it just doesn't have a global route. There is nothing to stop devices adjacent to your wan interface (ie other customers) from manually adding a route to your RFC1918 address space via your firewall. Will that traffic be allowed? that depends on the device and its configuration, have you ever tested this scenario? probably not.

NAT is a hack to get around a shortage of address space, nothing more. Once the shortage is gone there's no more need for NAT. That's why although NAT with IPv6 is possible, it's very rarely used because you no longer have any valid reason to use it. If you are think there are any other reasons to use NAT then you need to brush up on your network knowledge because a lot of smarter people than you or I are saying to avoid NAT and designing systems (eg IPv6) to fix the problems it causes.

US government advice is to avoid the use of NAT because of the extra complexity it introduces, which actually reduces security:

https://media.defense.gov/2023/Jan/18/2003145994/-1/-1/0/CSI...

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#490
post #442
post #433

Earlier quoted context omitted.

You're thinking small.. In an organisation of any significant size, remembering legacy IP is much worse than v6. Chances are you will have lots of disparate legacy blocks, some starting 1.x, some starting 80.x etc. Then you have all the RFC1918 space, and the possibility of overlapping address space in different areas of the business. Then you have to keep track of translations, so an internal address 10.1.1.1 could…

Yeah I get it. At an organization your size, you want IPv6. I was illustrating why there is zero incentive for 99.99% of people to not care, which is the reason why it isn't getting adopted. If moving my home network to IPv6 came along with some incentives -- e.g. significant tax breaks, free symmetric gigabit for a year for IPv6 traffic, discounts on rent, tax-free early IRA distributions to buy networking equipment…

The point is until everyone moves to IPv6, the rest of us are stuck having to support dual stack - which is expensive (see the recent story about an ISP supporting a tribal reservation who had to spend an extra $300k and wait 11 months to support legacy IP) and introduces complexity/risk.

For a small network it makes no difference, everything is auto configured, mdns is used to lookup names, you can makes your hosts ::1 ::2 etc if you want to. Many ISPs around the world provide IPv6 by default, and users are using it without even realising, so it is being adopted just not fast enough. Global usage is around 42% based on published stats, and is well over 50% in many countries, as high as 80% in some.

IPv6 does provide benefits to end users, it reduces cost for the ISP and makes end to end connectivity viable which opens up a whole new set of opportunities. End to end is immensely beneficial for gaming, voip etc. Having everything centralised because users are encumbered by NAT is a big problem - increased latency, high costs (recouped from the users somehow - eg selling their data), single point of failure, applications which become useless once the central servers are shut down etc.

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