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Enabling IPv6 support for IPv4-only apps on Linux

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Re: Enabling IPv6 support for IPv4-only apps on Linux

#131

Post by pavel_odintsov »

sgjohnson wrote: post #20
heartjudytenuta wrote: post #6

"To prove that IPv6 is ready for production use, I built a second PC so I can access the IPv4 Internet"

This is actually a very good workaround/transition mechanism, because it lets you go fully IPv6 native, keeping the translation layer for things that absolutely must use IPv4. And after transition is done, in theory, all you’d do would be turn off the translation box. In practice you’ll have to keep it up until the end of days, but that’s a separate matter.

Thank you very much for approving my idea!

Re: Enabling IPv6 support for IPv4-only apps on Linux

#132

Post by pavel_odintsov »

usr1106 wrote: post #12

ssh 64:ff9b::1.3.3.7 What address syntax is that? I mean I can easily guess what it means, but I wasn't aware such mixture exists. Do connect(2) and friends support that?

Thank you very much for this question. I've rewrote and improve my article to cover exactly this topic: https://pavel.network/building-gateway-to-access-legacy-ipv4...

Re: Enabling IPv6 support for IPv4-only apps on Linux

#133

Post by pavel_odintsov »

ok123456 wrote: post #120

Having to do an LD_PRELOAD to front run system calls in order to support IPv6, tells you that IPv6 is just fundamentally broken.

It was more about way to fix some very broken tool. ssh was just an example. It may be proprietary app without source code available.

Re: Enabling IPv6 support for IPv4-only apps on Linux

#134

Post by hot_gril »

hatch_q wrote: post #127
lazide wrote: post #119

Earlier quoted context omitted.

Every firewall I’ve dealt with since forever has default deny on inbound traffic, state full allow for outbound connections. Regardless of NAT or not, and regardless of how cheap it is.

Name one vendor? I can name you 3 that don't. Zyxel, Ubiquiti, Mikrotik. Also anything wrt based (eg. dd-wrt). In fact one of the warnings on dd-wrt official IPv6 tutorial: """ Keep in mind it can be dangerous to enable IPv6 without also having a firewall on each client that handles IPv6 packets, or having ip6tables on your router to filter incoming connections. ip6tables is NOT included by default with DD-WRT, which…

This is my concern too. NAT is nice because it's stupid and secure by default. No matter how you misconfigure it, the router simply doesn't know where to forward inbound packets to, unlike a firewall which has to actively block. My assumption for routers is that they won't handle firewalls right, especially the many cheapo ones.

Re: Enabling IPv6 support for IPv4-only apps on Linux

#135

Post by ianburrell »

giancarlostoro wrote: post #94

So when and how will IPv6 become the absolute standard? I presume an act of government law would do it, otherwise, if tech companies got together to force the change en masse, that would also do it. I don't understand why IPv6 has not become more prevalent over the coming years. Seems like we're taking baby steps and growing in our dependence on IPv4 IPs, although based on other comments here it sounds like at least…

IPv6 has been silently growing. If Hacker News supported IPv6, there is a good chance you would be accessing it with IPv6. The problem is that may have hit a plateau with the easy migrations. The issue is that there is no incentive for most businesses to make switch.

I was thinking that there should be movement that IPv6 is the new default protocol. That includes requesting IPv6 from sites. Also, lots of docs on how to enable IPv6 with routers, program to label gear as IPv6-ready, and persuading manufacturers to enable IPv6 by default.

Finally, have best practices for IPv6 on corporate networks. With NAT64, it is possible to have IPv6-only network with IPv4 on the edge. I think it needs docs that describe how to do it, and lots of work in changing opinions of network engineers.

Re: Enabling IPv6 support for IPv4-only apps on Linux

#136

Post by dementik »

finaard wrote: post #53

Would be interesting to know which applications actually have problems with v6 - the example with directly using a v4 IP is more a user error, not an application issue. I pretty much stopped submitting patches enabling v6 functionality to various projects back in 2005 as everything I cared about was working at that point. (Side note, I was just trying to search a few of those - but seems that period pretty much doesn…

Colima on mac is struggling with ipv6. Not sure what component is responsible, but I have been unable to connect ipv6 hosts from colima containers.

Re: Enabling IPv6 support for IPv4-only apps on Linux

#137

Post by janc_ »

SSLy wrote: post #73
BlueTemplar wrote: post #66

Earlier quoted context omitted.

Please name and shame software/hardware that doesn't support IPv6 released after 2017 (when the IPv6 standard was finally finalized).

Any android phone

What do you mean? My Android phone does IPv6?

Re: Enabling IPv6 support for IPv4-only apps on Linux

#138

Post by heartjudytenuta »

giancarlostoro wrote: post #91
kuon wrote: post #86

Discord hardcodes ipv4 addresses and will not work for webrtc calls in DNS64 setup. In 2023 I consider it an insult to the internet as a whole.

I'm of the opinion that IPv6 is old enough that the fact we have not hopped to it yet means its not happening anytime soon. I wanted it back in 2008 when I first learned about it, and I know its older than that (90s iirc) so its either going to come one day "abruptly" by force and break half the internet, or people will do hacks to maintain IPv4 as is. I think the only way IPv6 will ever become mainstream is if eithe…

China has mandated moving to single-stack IPv6 by the end of the decade.

It is not well publicized.

It turns out when you have a government that can tell you "move to IPv6 or we'll have your legs broken and your family thrown in prison" it's a bit easier to get things moving.

Re: Enabling IPv6 support for IPv4-only apps on Linux

#139

Post by ianburrell »

kuon wrote: post #96
giancarlostoro wrote: post #91

Earlier quoted context omitted.

I'm of the opinion that IPv6 is old enough that the fact we have not hopped to it yet means its not happening anytime soon. I wanted it back in 2008 when I first learned about it, and I know its older than that (90s iirc) so its either going to come one day "abruptly" by force and break half the internet, or people will do hacks to maintain IPv4 as is. I think the only way IPv6 will ever become mainstream is if eithe…

Yeah, we need more incentive. Ipv6 is harder to implement yes, it is true, there is no point in denying this and arguing it solves tons of problem (it does). Most companies have ipv4 experience and it's just simpler. There must be some political pressure to make it move. But "hopefully" the economical pressure is starting to build up, a lot of providers are cheaper in ipv6 only configuration. Still, for a company lik…

One thing that might help is government regulation that any ISP using CGNAT must offer IPv6. Customers should get public IP address, single IPv4 or /64 IPv6.

Another would be that government customers need to have IPv6-enabled sites. This could get a lot of companies to add IPv6 hosting.

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