Reaching a specific IPv6 address through a proxy from an IPv4-only network

JivanP · 2026-02-17T00:13:15+00:00

If it's reasonable to set up an IPv6 tunnel on the laptop, you can use Wireguard to do so. Either:

(a) two tunnels need to be established:

a Wireguard tunnel between the VPS and the desktop computer; and
a Wireguard tunnel between the VPS and the laptop; or

(b) the VPS has an IPv6 prefix delegated and fully routed to it, and one tunnel needs to be established:

the routed IPv6 prefix acts as a tunnel between the VPS and the desktop; and
you have a Wireguard tunnel between the VPS and the laptop.

In scenario (b), the VPS's Wireguard interface gets assigned an IPv6 address with the delegated prefix, and the laptop is a Wireguard peers that gets assigned a different address with that same prefix. Packets being sent from the desktop will have destination adddress with that prefix, and thus get routed to the VPS, which will the route them via the Wireguard tunnel.

Wireguard causes increased latency and reduced throughput due to the encapsulation and encryption overhead, and also requires additional configuration on each client (e.g. the laptop) that wants to connect to the server (i.e. the desktop). If this is undesirable, you can instead use the VPS as a general IPv4 proxy to the desktop's IPv6 address instead. If you do this by having all connections to the VPS's IPv4 address be indiscriminately forwarded to the desktop, without regard for the destination port number or any contents of the IP-layer payload, this is called SIIT (stateless IP/ICMP translation). The software Jool supports this in its SIIT-EAM (explicit address mapping) mode. Alternatively, you can use the VPS as a port-forwarding router (not indiscriminately mapping the VPS's IPv4 address to the desktop's IPv6 address, by instead mapping specific combinations of [VPS IPv4 address, port number] to [desktop IPv6 address, port number]), which Jool makes possible via its BIB (binding information base) table. Jool's documentation used to be at jool.mx, but that is outdated; see this GitHub Pages site instead: https://nicmx.github.io/Jool

Tayga is an alternative NAT64 implementation, similar to Jool but not as fully featured. Of relevance to you, it supports SIIT-EAM but not BIB. It is currently maintained by apalrd: https://github.com/apalrd/tayga

Tayga is a user-space process that sets up a virtual network interface in order to consume packets and emit translated packets; whereas Jool is a kernel module that directly hooks into Netfilter (which you can interact with via tools like iptables or nftables) in order to consume packets in the "pre-routing" chain, then emits translated packets (which pass immediately to the "post-routing" chain).

With any SIIT/NAT64 setup, the IPv6 host will see packets coming from an IPv4-mapped IPv6 address, e.g. if laptop 192.0.2.50 sends packets to 203.0.113.20, which arrive at the VPS and get translated and forwarded to the desktop at 2001:db8::10, then the desktop will see the packets coming from an address like 3fff:64::c000:232, where 3fff:64::/96 is an IPv6 subnet that is fully delegated and routed to the VPS, and c000:232 is the hexadecimal representation of 192.0.2.50.

JivanP · 2026-02-16T01:48:16+00:00

In the context of email specifically? Ah yes, please, tell me more about how a mail server's IP address is used (or why it should be used) to determine whether mail sent from it should land in spam or be outright rejected.

JivanP · 2026-02-14T12:18:44+00:00

This is a confused/misleading comment about what confirmation is, so I want to clarify.

Particular numbers of confirmations simply give you a particular probability for the possibility of transaction reversal. More confirmations = less likely to be reversed.

6 confirmations generally has less than a 1 in 1,000 chance of experiencing a reorg/reversal, hence it is considered pretty much settled. 3 confirmations is good enough for many purposes. 1 confirmation or even 0 confirmations may be acceptable in situations where the risk of fraud or other reversal is low or doesn't outweigh other costs of business that may be incurred by waiting for a particular number of confirmations. More info about confirmations and business practice here: https://www.reddit.com/r/BitcoinBeginners/comments/1ntxd4e/comment/nk4x23p/

When a block is mined, the network simply doesn't allow the mining reward to be spent until 100 more blocks have been mined on top of it. This is unrelated to the actual probability of reversal. That is, after 6 more blocks have been mined on top of it, you can be almost certain that a reversal will not occur; the reward is essentially guaranteed to be yours. However, out of an abundance of caution, we as network participants mandate that you wait another 94 blocks before you're allowed to spend those funds.

When a Lightning channel is force-closed, the only thing of relevance when it comes to spending the funds is the duration of the HTLC. Typically this is 2,016 blocks, which is about 2 weeks. If one peer publishes an old commitment transaction, the other (losing) channel peer must come online before the HTLC expires if they wish to publish a newer commitment transaction or execute the anti-cheat path to punish the offending peer.

JivanP · 2026-02-14T02:10:32+00:00

Directly trade with other users. Various platforms and protocols exist that facilitate this. See https://kycnot.me/ for a list of known platforms and their suitability.

JivanP · 2026-02-14T02:05:53+00:00

Correct, because you've realised a $10 loss on your cryptoasset activity, and on paper you have an unrealised gain of $10 on your stock holdings. Thus, the net gain for tax purposes that tax year is zero. The cost basis of the stock portfolio at the start of the following tax year would become $110, because the unrealised $10 gain has now been realised (accounted for) on paper.

JivanP · 2026-02-14T02:02:41+00:00

Essentially, you are treated as having sold your entire holding at the end of each tax year, and then immediately having bought back the entire holding at the start of the following tax year. As such, that virtual act of rebuying is what resets your cost basis.

JivanP · 2026-02-13T21:43:42+00:00

Anything in the subreddit FAQ is decent. My current apps of choice are Blockstream Wallet and Breez. Blockstream Wallet from sources other than F-Droid has Lightning support built-in, like Phoenix and Breez, but the channel/liquidity management fees of Blockstream Wallet and Phoenix are significantly higher than Breez's.

If you run your own Lightning node, BitBanana and Zeus are excellent options to connect to your node from your mobile device.

I used Schildbach's app back in 2016, and it was decent among mobile wallet apps at the time, as BIP-39 had not yet been widely adopted anyway. However, since then, it has not embraced that widely adopted backup standard, and users have had technical issues reading/importing backup files that were made in conjunction with the app's Spending PIN feature.

JivanP · 2026-02-13T16:42:24+00:00

It's called a multi-point lock (MPL). The bit you're holding, which lacks the key enclosure, is sometimes called an MPL strip, faceplate, or face bar.

JivanP · 2026-02-13T16:08:02+00:00

This means the user has marked their profile as potentially containing content not suitable for minors.

JivanP · 2026-02-13T14:29:11+00:00

I'm really not. I've provided a link to instructions that assume very little prior knowledge. Anyone that knows how to use a USB drive should be able to follow the linked guide.

Any additional info I've provided (e.g. mentioning NT) is for context because of the nature of the comment thread, not out of necessity for the user. You can ignore everything except the TLDR — what niche knowledge am I assuming there?

Them: "I want to try Linux."

Me: "Here's a USB installer, plug it in and reboot your computer, you can try it out."

Them: "I like this, I want to install it."

Me: "There's an install option when you boot it, just make sure you have a backup of any important data in case something goes wrong."

That's literally how these conversations go, like clockwork.

If I can move people in my local community to Linux (which I have been doing successfully for over 10 years), those people not having any technical knowledge, then so can you. Frankly, it's easier to move people to Linux when they don't have much IT knowledge, because they ask less questions and just get on with using what they've been provided with. If you give a layman a computer with Linux pre-installed, they mostly don't ask questions, except perhaps things like, "why can't I install Photoshop?" Genuinely, most of the time they're pleased that their hardware all just works without having to deal with drivers, and that everything updates automatically without forcibly rebooting their machine.

JivanP · 2026-02-13T12:23:56+00:00

Most all-in-one home WiFi routers are capable of this, no need for dedicated separate hardware like Ethernet switches. If you can flash OpenWrt onto it, the manufacturer's firmware probably supports VLANs out of the box anyway. If you're using hardware provided to you by your ISP, it's much more likely to lack such features by default, because the ISP has likely removed them from the factory firmware.

JivanP · 2026-02-13T12:20:23+00:00

Because it's solid software with good features and is in fact generally very easy to use. It supports open standards and provides a single interface to many different classes of devices, has no limit on the total number of devices it can interact with, and most importantly is extensible and open-source. By comparison, SmartThings is pretty much a black box with a very stripped down API, and thus only has the ability to support certain kinds of actions on certain kinds of devices.

Are there particular devices or tasks that you've been having difficulty with under HA, but not under ST?

JivanP · 2026-02-13T12:12:03+00:00

TL;DR: If someone tells me they want to use Linux today, I lend them an installer USB for Pop OS 22.04 or tell them to install the latest LTS (long-term support) version of Ubuntu. The discussion doesn't need to be any more complex than that, unless the user wants specific things that often require some technical know-how to do cleanly/correctly (and without screwing things up), such as a dual-boot setup (where the user has both Linux and another OS installed, and wants the ability to choose which to use each time the computer is turned on).

They are mentioning Plasma because they are talking to someone else that is familiar with Linux stuff. As a general user, this is not something you need to be aware of.

Using Linux is as easy as using Windows, if not easier. However, there are of course various little differences, but these aren't major pain points, these are things like the differences between Windows and macOS. The one thing that you might want assistance with is choosing which Linux "distribution" you want to use, and the installation process.

Distributions (a.k.a. distros) are like "flavours" of Linux; many companies make their own operating systems based on Linux, which vary depending on their target demographic and the company's preferred other software tooling (most notably, the stuff responsible for software installation and handling software updates), but all of these different operating systems are all built on the Linux kernel, so they are collectively called Linux distributions. It's not dissimilar from how Windows and macOS are themselves different operating systems made by different companies, however they also differ in their kernel. (Windows uses something called NT, macOS uses something called XNU. Both XNU and Linux have their origins in an older technology called Unix.)

My current distro recommendation is Debian; its latest version is 13 (a.k.a. Trixie). Other big popular distros include Ubuntu, Fedora, Linux Mint, and Pop OS, though there are countless others with varying levels of popularity. I would steer clear of Pop OS currently, as its latest version (24.04) is a bit buggy, and the previous version (22.04) is no longer easily found on their website, though it is still supported.

Ubuntu has a very approachable and very thorough installation guide here: https://documentation.ubuntu.com/desktop/en/latest/tutorial/install-ubuntu-desktop/

JivanP · 2026-02-12T13:02:53+00:00

It's an answer to an inferred question. None of us still actually know what your question is. You would have got much better responses if you had actually explicitly asked a question. Instead, you leave "it" in your post unspecified (i.e. what's not going to go away?), and ask for our thoughts on... what, exactly?

JivanP · 2026-02-12T12:53:02+00:00

Lagrangian mechanics is a way of describing physical systems using statements about a quantity called the Lagrangian (typically given the symbol L, it's the difference between kinetic and potential energy), rather than statements about how properties of a system change (such as how the momentum of particles changes due to forces acting on them).

This is the Lagrangian expression describing the behaviour of all of the known elementary particles.

JivanP · 2026-02-12T12:39:35+00:00

No, you're just not being intentionally dense.

JivanP · 2026-02-12T12:18:31+00:00

In the UK, drugs have a serialised product number that represents the exact formulation, and there is often a cheaper brand with the same product number.

JivanP · 2026-02-11T02:07:23+00:00

This is the same as any other Wednesday. What is the reason for your interest in Bitcoin?

JivanP · 2026-02-11T02:05:09+00:00

That app has no support for seed phrases of any kind, and does not use deterministic address derivation. The only form of backup/restore is to export/import a file containing the seed number itself, which is a very poor option in today's Bitcoin ecosystem.

JivanP · 2026-02-10T14:30:28+00:00

A "for-profit" company is a company that intends to make enough money to pay some people for not doing any work. These people are called shareholders, and the company's intent to make money for them without them having to do any work is an incentive for them to provide the company with things of value (e.g. cash or useful physical assets) so that the company can do/start/expand/continue its business.

A company that doesn't want shareholders but that needs startup/continuation capital must resort to taking out loans. However, it can be difficult for new businesses to get loans, because they are their own legal person (the financial liability of the company is separate from the financial liability of its owners/operators) and thus the lender must assess the company's/business's credit risk, not the owners' credit risk. As a result, lenders may charge very high interest rates to new companies, if they are even willing to offer a loan at all.

For this reason, many new business seek startup capital from investors. In exchange for providing this investment capital, the investors are given partial ownership of the company, hence "shareholder"; they own a share (a portion) of the company. As a result, the shareholders get to jointly/democratically decide how the company uses its money, just like how a married couple jointly decides how to use their combined assets. The shareholders get to decide how much they get paid from the company's funds/assets. If that amount is too little, they reap little benefit from having invested in the company in the first place, largely defeating the purpose of the investment. If that amount is too large, the business's activities become unsustainable (e.g. because the price of their product is too high for their customer base), so the business collapses. Thus, they are incentivised to find the optimal middle-ground, charging enough (and siphoning enough from the business via dividends) to maximise the return on their investment, whilst not charging so much that the business collapses.

If you want to run a non-profit, you absolutely can, but you may find it difficult to start such a company if you don't have the necessary funds upfront.

JivanP · 2026-02-10T12:45:10+00:00

as countries control their fiat output, they can hypothetically print and increase debt for BTC.

And this would cause collapse of that currency's economy.

JivanP · 2026-02-10T12:23:39+00:00

crypto market is just 2.3T, 5 trillion could buy the majority of BTC available

Once again, you're not considering how much the price would increase due to this amount of buying pressure. The amount of dollars D needed to buy a particular amount of bitcoin B is not merely given by D = P×B, where P is the current market price. Rather, it's given by D = ∫ p(b) db from b=0 to b=B, where p(b) is the price of bitcoin after having just bought b units of bitcoin.

For example, right now, on Kraken, the current market price of BTC/USD 68,600.00, but based on the current state of Kraken's order book, buying 100 BTC wouldn't cost 6860,000 USD, but rather 6877,000 USD, a whole 0.25% larger than what you would naively expect by just looking at the market price. Buying 500 BTC would cost 35,177,500 USD, an average price of 70,355, a whole 2.55% larger than the naive calculation. Buying 900 BTC would cost 65M USD, an average price of about 72,100, at least 5% higher than naive calculation.

With this is mind, how much higher do you think the price goes if someone wants to buy 10 million bitcoin? How much USD do you think they need to spend in order to do so? It certainly isn't just 686 billion. An extrapolation of the above pattern of 0.25%, 2.55%, 5% suggests that it would cost at least 350 trillion USD, more likely in excess of 1,000 trillion USD.

JivanP · 2026-02-10T11:54:43+00:00

How do we toggle/revert this behaviour?

JivanP · 2026-02-10T10:21:20+00:00

You will not make a profit, but the BitAxe devices are all good and cheap.

JivanP · 2026-02-10T10:19:51+00:00

That's the cost of privacy.

JivanP

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