You don't need to have ipv6 support by your provider, it's ipv6 over ipv4. You only need your hardware (phones, laptops) and software (OS, servers, clients) to support ipv6.
I use it to play LAN games with my friend from other country, kind of like Hamachi, but FOSS.
It just works. You install yggdrasil on all your devices that support ipv6, you write down ipv6 of all devices you want to connect to, you type the ygg ipv6 and connect, as long as ports are open.
I wish I could switch to Inkscape, but it's not there yet.
It is really good lately and only getting better, but there are 2 major issues I have with Inkscape.
Tabs (as in, tabulation, the \t character) in text objects. You can find workarounds, like splitting your text into multiple objects and aligning them on your canvas, but it's just not as good as being able to align your text using proper text alignment tools. Tabulation doesn't work in Inkscape because it's not in SVG spec, AFAIK.
Object styles. Again, there are workarounds, but they're not as good. Can you create a text style called "numbering", use it to number a lot of stuff in your document, then just change font family (or make it italic, or bold) all of the numbers at once by changing the "numbering" style? I don't think it's currently possible. Sure, inkscape is not a word processor. But can you make an object of style "banner" with a blue gradient fill, orange 2 px stroke and 50% transparency, use it multiple times, then when you need to change from blue gradient to red gradient just change the "banner" style? Again, there are ways to achieve this, but if you do this kind of stuff, inkscape is just not ready to replace your tools.
Don't get me wrong, I really want to switch to FOSS all the way and wait for these things to get implemented. As soon as they're there, I'll be the first to make the switch. But it's not now, unfortunately.
Unless you seek trouble and do stuff without knowing what you are doing (like blindly copy pasting commands from internet into your terminal), it generally just works.
It's not as good as those distros where all packages come preconfigured for you to work nicely together, so if you want to build a custom system (like, choose your DE/WM/panels/widgets etc), you have to configure all of that to intergate nicely. But you could always just install KDE and everything is pretty stable there, same as in any other KDE based distro.
Oh, I have found pwnat before, but it's not available for windows, also most people say that it doesn't work anymore because most routers patched the behavior that made it work IIRC.
What's the easy way to know if two peers are directly connected without measuring ping time and guessing?
But we already have decentralized encypted chat, it's XMPP.
Is yours truly P2P? What about clients behind NAT? Does it use STUN/TURN servers?