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Why IPv6 is so complicated

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Re: Why IPv6 is so complicated

#391

Post by adrithmetiqa »

PunchyHamster wrote: post #379
everdrive wrote: post #372

This is the only topic that tempts me to create a throwaway account. (I have not given in) None of the IPv6 proponents are willing to acknowledge that IPv6 is a pain. All of them seem to have gone to some secret seminar somewhere where they receive their talking points: - Everyone who dislikes IPv6 doesn't know how NAT works and thinks it's the same as a firewall. - There's absolutely no downside whatsoever to being…

You forgot important thing: There will always be some security guy yelling that leaking your internal IP structure is bad. There will also be another clown that does IP whitelisting as security measure and refuses to just whitelist single /64|/24 network "because it is too wide" (I literally had this conversation last week with one of the clients) > - The entire internet would be hosting home servers if not for the e…

It would have been a success if they just called it ipv5.

Re: Why IPv6 is so complicated

#392

Post by zadikian »

msla wrote: post #388
bborud wrote: post #382

Why are we, in 2026, still talking about ipv6? It is time to give it up and start over. Yes, it is unlikely we can agree on an ipv4 successor. But at this point we should be able to agree ipv6 is not going to be it.

For the same reason we, in 2026, are still talking about Java.

Java bent a lot to accommodate. There are lambdas and records which violate the old OOP rules, and now virtual threads which were sorely missing for things like web backends.

Re: Why IPv6 is so complicated

#393

Post by MaKey »

speedgoose wrote: post #380
MaKey wrote: post #318

Earlier quoted context omitted.

You could have spent a bit of time on debugging the issue. This would have been a great learning opportunity.

I agree, but debugging IPv6 issues is pretty far down on the list of things I want to learn.

Which european cloud provider is it?

Re: Why IPv6 is so complicated

#394

Post by thayne »

convolvatron wrote: post #353
thayne wrote: post #349

Earlier quoted context omitted.

When ipv6 was first created DHCP and NAT were new and not widely deployed. They weren't trying to "fix" them, they solved the same problems independently. And if you need NAT or DHCP, there isn't any reason you can't use them with ipv6. DHCP6 had been around for a long time.

that's not at all true. DHCP was very much part of the operational canon of the internet at the time, which is why it persisted as a model. V6 really wanted to back that out so that networks 'just worked' without depending on an administrator to manage that local service. NAT was already in use, and a substantial motivation for the IPv6 work was to provide an alternative before it got too entrenched, which sadly fail…

The RFC for dhcp was published in 1997, two years after the first RFC for IPv6, and three years after work on IPv6 started.

Re: Why IPv6 is so complicated

#395

Post by johncolanduoni »

zadikian wrote: post #387
johncolanduoni wrote: post #370

Earlier quoted context omitted.

This already exists in two forms, and has for basically the entire history of production dual stack deployments. The first are IPv4 mapped addresses (of the form ::ffff:x.x.x.x) which instruct the local machine’s network stack to use a local IPv4 address to communicate to the server. This still requires each machine to have a routable IPv4 address (though not necessarily a public one - it can be used with a NAT44 rou…

I want something:x.x.x.x to get routed to me over v6 if I had x.x.x.x in v4, as the default and recommended way of contacting an ipv6 host, without needing additional config or middleboxes. Neither NAT64 or NAT46 do this really, and they're presented as alternatives rather than the native way. The closest was 6to4. rfc6343 goes into why that got deprecated. You'd either have "router 6to4" which required additional se…

You can do this quite easily on all the major OSes by opening a single dual-stack socket. On most Linux distributions that is the default, and then mapped addresses will work fine if the machine has a v4 address or a 464XLAT configuration. This has been the case for about 20 years.

Re: Why IPv6 is so complicated

#396

Post by globular-toast »

everdrive wrote: post #372

This is the only topic that tempts me to create a throwaway account. (I have not given in) None of the IPv6 proponents are willing to acknowledge that IPv6 is a pain. All of them seem to have gone to some secret seminar somewhere where they receive their talking points: - Everyone who dislikes IPv6 doesn't know how NAT works and thinks it's the same as a firewall. - There's absolutely no downside whatsoever to being…

This comment would make more sense if you said why IPv6 is a pain. It just works for me.

Re: Why IPv6 is so complicated

#397

Post by zadikian »

kstrauser wrote: post #390
everdrive wrote: post #372

This is the only topic that tempts me to create a throwaway account. (I have not given in) None of the IPv6 proponents are willing to acknowledge that IPv6 is a pain. All of them seem to have gone to some secret seminar somewhere where they receive their talking points: - Everyone who dislikes IPv6 doesn't know how NAT works and thinks it's the same as a firewall. - There's absolutely no downside whatsoever to being…

> Everyone who dislikes IPv6 doesn't know how NAT works and thinks it's the same as a firewall. It would be easier if IPvOld proponents didn't keep saying that it is. Seriously, every time this topic comes up, at least one person expresses horror at the idea of running IPv6 without a firewall, unlike their safely NAT-firewalled IPv4 setup. > There's absolutely no downside whatsoever to being publicly addressable. I w…

"Who are all these people who don't like using DNS?"

"It's always DNS," and mDNS is finicky too. At least, not reliable enough that I can never look at addresses again.

Re: Why IPv6 is so complicated

#398

Post by [deleted] »

everdrive wrote: post #372

This is the only topic that tempts me to create a throwaway account. (I have not given in) None of the IPv6 proponents are willing to acknowledge that IPv6 is a pain. All of them seem to have gone to some secret seminar somewhere where they receive their talking points: - Everyone who dislikes IPv6 doesn't know how NAT works and thinks it's the same as a firewall. - There's absolutely no downside whatsoever to being…

[deleted]

Re: Why IPv6 is so complicated

#400

Post by kazen44 »

Ekaros wrote: post #303
dgoodell wrote: post #279

Earlier quoted context omitted.

IPv4 + all the other stuff you need to actually make it work in the real world actually seems more complicated than IPv6 to me. Maybe they’re comparing the minimal implementation on a home network. But even then I’m not sure the claim holds up. People learned IPv4 when they were younger in a more incremental manner and take it for granted now.

ARP and DHCP really look really dirty whenever I look at them. Like pretty bad designs overall. From more neutral viewpoint it feels that whole stack would be better with something else than these clear hacks.

arp simply breaks down in very large networks aswell.

Think about things like the following: you are a datacenter and are providing connectivity to the internet for your customers. Each customer get a vlan with a specific ip prefix attached to it. You prove the gateway for each customers subnet.

ARP crosses the L2 vs L3 boundary to do succesful address resolution. The problem this creates in large (mainly datacenter) networks is that a router needs to do arp resolution for for a LOT of networks. (i am talking about 100's of networks in past, many thousands with something like an EVPN vxlan).

Why is this a problem? Layer 2 lookups are usually done in the forwarding plane, and ARP resolution is usually a routing engine task. Doing it this way is very expensive compared to the IPV6 way of doing things. (multicast based address resolution).

The router only needs to send out one multicast packet per vlan, instead of doing arp resolution for each specific host in the vlan.

In modern datacenters this is "fixed" by doing arp suppression, which is a whole other level of hackary added on top of it.

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