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Enabling IPv6 support for IPv4-only apps on Linux

blog.apnic.net

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

#151
post #33

Does anyone have a good write up of taking ones home network and going 100% ipv6 including dealing with iot devices that can't? I am thinking of doing it but I have a huge mix of devices from linux to windows and servers.

I'm 100% the opposite. Define everything ipv4, turn off ipv6 and have one set of private ip addresses, one set of firewall rules and NAT at the firewall/router.

Yep, first thing I always do on a new router or PC is get out of the dual stack situation by disabling v6.

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

#152

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…

When they need to solve the address space crisis, they can make a "v4.1" that's just v4 but with an expanded address space. Existing addresses and decimal format stay; NAT DNS DHCP ARP etc stay mostly the same aside from supporting longer addresses. Cloudflare DNS is still 1.1.1.1, my private ip is 192.168.1.2, public 71.177.17.171, some new ISP hands out 11.127.13.121.143.356 when they run out of shorter addresses,…

You know this can't work without having the same issues as IPv6, right? Take a look at the IP headers.

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

#153

Earlier quoted context omitted.

When they need to solve the address space crisis, they can make a "v4.1" that's just v4 but with an expanded address space. Existing addresses and decimal format stay; NAT DNS DHCP ARP etc stay mostly the same aside from supporting longer addresses. Cloudflare DNS is still 1.1.1.1, my private ip is 192.168.1.2, public 71.177.17.171, some new ISP hands out 11.127.13.121.143.356 when they run out of shorter addresses,…

You know this can't work without having the same issues as IPv6, right? Take a look at the IP headers.

They'd have to expand the header in a backwards-incompatible way, yes. IPv6's issues don't all stem from that. Changing all the existing addresses, adding new special kinds of addrs, trying to ditch NAT, and maybe even changing the human-readable format of addrs created most of this resistance. Asking someone to go v6 is asking for a whole network redesign, with an end result that isn't exactly simpler.

Swap in v4.1-compatible stuff and you'd be done. Sending to short address uses v4, sending to long uses v4.1.

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

#154

Earlier quoted context omitted.

Small places? When I disabled IPv4 a few weeks ago, I couldn't use: HN, GitHub, Reddit, Discord, Duckduckgo.

I don't have IPv6 enabled. Literally everything works.

Congrats on having a non-CGNAT Internet connection available.

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

#155
post #125

Earlier quoted context omitted.

> and its privacy extensions are anyway not something ISPs have been friendly to That is an argument for forcing ISPs to support SLAAC, so it's difficult to bill a customer based on the number of devices in their home. ISP-friendly often means user-hostile. If ISPs can deploy device-counting DHCPv6, then router manufacturers will respond with IPv6 NAT, and then the IPv6 landscape will be as shitty as IPv4.

Device counting has always been possible with IPv4 routers, and yet I don't know of a single ISP which does this. To be clear, I'm talking of ISP-provided (usually wifi) routers, which at least in my country are extremely common. Those could receive an IPv6 prefix and do DHCPv6 inside your own network.

The concept of an IPv4 NAT router exists today because people in the '90s wanted to connect multiple devices without permission from their ISP. SLAAC lets you extend a network without permission using ND Proxy, whereas DHCPv6 IA_NA can only be extended using NAT.

So I think SLAAC is good because ND Proxy is less evil than NAT.

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

#157

Earlier quoted context omitted.

You know this can't work without having the same issues as IPv6, right? Take a look at the IP headers.

They'd have to expand the header in a backwards-incompatible way, yes. IPv6's issues don't all stem from that. Changing all the existing addresses, adding new special kinds of addrs, trying to ditch NAT, and maybe even changing the human-readable format of addrs created most of this resistance. Asking someone to go v6 is asking for a whole network redesign, with an end result that isn't exactly simpler. Swap in v4.1-…

If you expand the header in a backwards-incompatible way, you have to upgrade all the routers and endpoints. You'd need to extend other protocols, like BGP and OSPF, to even route your "v4.1" prefixes. You'd have the exact same dual stack issues as you do with v6.

Why bother? IPv6 is available today and has been here for over 20 years. The truth is it is actually simpler to deploy than v4. For example, the address format makes it easier to understand subnetting (because it's hex.) NAT is an abomination and we should be glad to see it go: end-to-end connectivity is how the internet is supposed to work. I remember the old days (the 90's) where we all had public IP addresses on our desktops. VPNs are much simpler: there's no potential for overlapping RFC-1918 addresses because v6 is globally unique. I could go on.

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

#158
post #96

Earlier quoted context omitted.

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.

> 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.

My understanding is they largely do. It's the ISPs that have enough IPv4 addresses that don't feel a need to upgrade, and the website operators who $3/server/month for an IPv4 address is a rounding error.

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

#159
post #96

Earlier quoted context omitted.

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…

If ipv4 is just simpler and people prefer it like you say, that's a sign that v6 isn't a good option for replacement.

Some of this is unavoidable while fixing the scaling problems of IPv4. Longer addresses are never going to be preferable for users over shorter addresses, but addresses are necessarily going to be longer than IPv4 if it's going to support more devices.

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

#160

Earlier quoted context omitted.

Plenty of big sites have no AAAA record even

It can be easily sorted out with DNS64 and NAT64: https://pavel.network/building-gateway-to-access-legacy-ipv4...

I meant it more as damning the current level of commitment from big corps who could probably afford to dual stack
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