Why IPv6 is so complicated • Hacker News Board

Re: Why IPv6 is so complicated

#41

Post by eqvinox » Sat, Apr 18, 2026, 7:49 AM UTC

b112 wrote: post #22

lamonade wrote: post #17

Earlier quoted context omitted.

how do you encode 128 bits without making a long number? and not using hex?

Far easier to use ipv8, which just has 5 octets instead of 4.

We have that variant of IPv8, it's what CGNAT gives you, especially if you run MAP-E or MAP-T (which are technically not quite NAT, but kinda are, it's… complicated). You take some bits from the port number and essentially repurpose them into part of the address.

It's a nice band-aid technology, no less and no more.

Re: Why IPv6 is so complicated

#42

Post by smolder » Sat, Apr 18, 2026, 7:49 AM UTC

mort96 wrote: post #31

smolder wrote: post #19

It's not. I learned how IPv6 worked SO LONG AGO that I really can't understand remaining confusion.

It's not complicated because you understand it? Okay then

Not much more complicated than IPv4. There are more bits. The addresses are longer. It's not hard to grasp if you understand the prerequisites to understanding networking in general.

Re: Why IPv6 is so complicated

#43

Post by izacus » Sat, Apr 18, 2026, 7:51 AM UTC

It is like it is because:

* It was designed by people who didn't have the full picture and were missing representatives from hardware vendors, small businesses, home network admins and a bunch of other people that will be affected by design.

* It was designed by people who didn't consider the cost of migration and the amount of work that would require (see previous point).

* It was designed by people who lived in an ivory tower of "noone will run dual stack for a long time", "everyone will love to run two completely separate network designs".

* It was designed on a premise that end-to-end, fully accessbile devices are something we actually want and won't cause privacy issues.

I think it should be a study material on how standards and designs by commitee can go wrong if they're not headed by people with extensive experience across the industry with enough authority to push for good solutions.

IPv6 tried to do too much (just like many software "let's refactor this legact code") and was done by people who didn't consider all perspectives and costs (again, like many less experienced architects trying to rewrite legacy software).

Re: Why IPv6 is so complicated

#44

Post by muvlon » Sat, Apr 18, 2026, 7:51 AM UTC

9dev wrote: post #20

muppetman wrote: post #11

This annoys me, especially the last “It takes at least 25 years” rhetoric. It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP. GPRS/HSDPA/3G/4G/5G They all rolled out just fine and were pretty backwards and forwards compatible with each other. The whole SLAAC/DHCPv6/RA thing is a total clusterfuck. I’m sure there’s many reasons that’s the case but my god. What does your ISP s…

> The whole SLAAC/DHCPv6/RA thing is a total clusterfuck. SLAAC is easily the thing I love most about IPv6. It just works. Routers publish advertisements, clients configure themselves. No DHCP server, no address collisions, no worry. What's bugging you about it?

What problem is this actually solving? I've deployed DHCP countless times in all sorts of environments and its "statefulness" was never an issue. Heck, even with SLAAC there's now DAD making it mildly stateful.

Don't get me wrong, SLAAC also works fine, but is it solving anything important enough to justify sacrificing 64 entire address bits for?

Re: Why IPv6 is so complicated

#45

Post by eqvinox » Sat, Apr 18, 2026, 7:51 AM UTC

rusk wrote: post #38

SkiFire13 wrote: post #14

Earlier quoted context omitted.

> Instead they expected humans to parse hex, which no one does Of all aspects of IPv6 you took the only one that doesn't complicate implementations and can easily be swapped if you wanted.

Wait til you’ve got to copy & paste em, or see em comingled with hw addresses

Wait till you find an application that accepts 1.65793 as an IPv4 address. Or 134744072.

  $ ping -c 1   1.65793
  PING 1.65793 (1.1.1.1) 56(84) bytes of data.
  64 bytes from 1.1.1.1: icmp_seq=1 ttl=54 time=1.56 ms
  
  --- 1.65793 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 1.560/1.560/1.560/0.000 ms

(by the way, this was way less of a dumb peculiarity back when IPv6 was designed)

Re: Why IPv6 is so complicated

#46

Post by threiw » Sat, Apr 18, 2026, 7:53 AM UTC

bryden_cruz wrote: post #28

I recently had to set up basic IP-based country detection in Nginx for a project. Parsing and handling IPv4 is trivial. The second I had to account for IPv6 string formats and update the Geo databases to match, the complexity just spiked for no good reason. It feels like we traded address exhaustion for parsing nightmares.

On one of my linux machines the "localhost:8080" did not work after new installation. It resolves to local ipv6 address, while server only listened on ipv4.

After this I go out of my way to disable, remove and nuke ipv6, out of every setup and deployment I do. Ipv6 is already quite complicated, but supporting TWO competing network stacks, with complicated pseudo compatibility, just multiplies unnecessary complexity!

Re: Why IPv6 is so complicated

#47

Post by Paracompact » Sat, Apr 18, 2026, 7:54 AM UTC

> Incidentally, "IPv8" proponents often ask why IPv6 didn't simply stick some extra bits on the front of IPv4 addresses, instead of inventing a whole new format. Actually, we tried that: the "IPv4-Compatible IPv6 address" format was defined in {{RFC3513}} but deprecated by {{RFC4291}} because it turned out to be of no practical use for coexistence or transition.

Any tl;dr on why/how the simplest solution imaginable would have been "of no practical use for coexistence or transition"? Granted, I understand the other points make a strong enough case by themselves.

Re: Why IPv6 is so complicated

#48

Post by zem » Sat, Apr 18, 2026, 7:54 AM UTC

lamonade wrote: post #17

muppetman wrote: post #11

This annoys me, especially the last “It takes at least 25 years” rhetoric. It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP. GPRS/HSDPA/3G/4G/5G They all rolled out just fine and were pretty backwards and forwards compatible with each other. The whole SLAAC/DHCPv6/RA thing is a total clusterfuck. I’m sure there’s many reasons that’s the case but my god. What does your ISP s…

how do you encode 128 bits without making a long number? and not using hex?

have that be the invisible bottom layer. come up with a list of 256 common words, one per byte, and have that be the human visible IP address. mentally reading a string of words, however nonsensical, is way easier than a soup of undifferentiated hex digits.

Re: Why IPv6 is so complicated

#49

Post by collabs » Sat, Apr 18, 2026, 7:54 AM UTC

JumpCrisscross wrote: post #24

muppetman wrote: post #11

This annoys me, especially the last “It takes at least 25 years” rhetoric. It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP. GPRS/HSDPA/3G/4G/5G They all rolled out just fine and were pretty backwards and forwards compatible with each other. The whole SLAAC/DHCPv6/RA thing is a total clusterfuck. I’m sure there’s many reasons that’s the case but my god. What does your ISP s…

> What does your ISP support? My ISP is Spectrum. They get a 0/10 on IPv6 support on this test page [1]. [1] https://test-ipv6.com

Is it possible that you own your own router and have at some point configured the router to turn up 6 off? I know it is turned off on my router because I had some issues with Verizon ipv6 and tp link in the past.

Re: Why IPv6 is so complicated

#50

Post by roenxi » Sat, Apr 18, 2026, 7:55 AM UTC

> There was also unnecessary confusion caused by a rather political decision to make IPv6 require support for IP Security (IPsec), which was an immature technology at the time. This was a definite brake on IPv6 deployment until it was dropped after some years.

I don't know anything about the IPv6 situation, but the way this paragraph just slots in so innocently foreshadows some long wordy Wayland retrospective document on why adoption was so slow where someone from deep in the community slips in 1 short "sure we tried to block screenshots and that might have caused some issues with adoption for some users" paragraph in the middle-end. The innocence of the admission is so mild and context-free that it somehow manages to make itself look guilty.