Tell HN: IPv6-only still pretty much unusable • Hacker News Board

Re: Tell HN: IPv6-only still pretty much unusable

#491

Post by Bluecobra » Thu, Dec 08, 2022, 3:33 AM UTC

justin_oaks wrote: post #237

yesco wrote: post #122

Earlier quoted context omitted.

A confusing aspect of IPv6 is that it's actually a much simpler protocol than IPv4, you often end up assuming you need to configure a bunch of stuff that you really don't have to. The most common example would be NAT, despite the complexity it adds to IPv4, people often get comfortable with idea of setting up complex subnet hierarchies and feel lost when that all just disappears with IPv6. The key things to remember…

Thanks, that helps a lot. This got me reading about IPv6 again. I'm trying to figure out how we'd set up an IPv6 network in the case where we have 1) Two upstream ISPs, mostly for failover, but could be loadbalanced too. 2) Internal servers with assigned DNS My initial thoughts were that for each of the two ISPs, each host (e.g. personal desktop or laptop) would use the IPv6 prefix and end up with two addresses. But…

You don’t have to be a large corporation to have your own IP space. Getting your own IP space assigned by an authority like ARIN and getting a BGP AS number is the way to go here. I think ARIN allocates out IPv6 space out for free or low cost. There are yearly maintenance fees involved but should still be affordable for a small business. If this is for home use, then yeah that would be overkill.

Re: Tell HN: IPv6-only still pretty much unusable

#492

Post by vlovich123 » Thu, Dec 08, 2022, 3:35 AM UTC

theamk wrote: post #480

Plasmoid wrote: post #458

Earlier quoted context omitted.

> Right now, most application software need non-trivial rewrite to add ipv6 support: That's not right. If you've been using the platform network libraries for things then IPv6 will just work with anything more recent than Windows XP. Unless you've been hardcoding IP length expectations then there is basically nothing to do. Seriously, use the platform libraries. They handle all the edge cases and stop storing IP addr…

Unless you are doing something super trivial, like making http/https requests to pre-defined URLs, your platform libraries will not help you. Your network servers need two explicit bind() calls for two different protocols, and some logic to select which ones to call, and your main accept() code needs to be able to handle two listening sockets... Theoretically you could create IPv6 socket only and accept both addresse…

Sorry. What? You’re claiming that the hard part is the parsing of textual ipv6 addresses to binary representation but these same algorithms would work on a hypothetical hand-wavy ipv4+ how? It’s extended so you’ve either got numbers > 255 (breaks parsing routines) or more dots (again breaks parsing routines). Either way you slice it you have to upgrade the parsing routines. And the hard part has not been the parsing routines. And you’d need to justify that what you describe about bound addresses doesn’t apply to a non-existent ipv4+.

It’s getting all the middleware routers, services, and websites to support both that’s been the challenge because it was a chicken and egg. ISPs didn’t want to do it. Websites wouldn’t do it because there were no customers. Carrier grade NATs bought another decade or two. Manufacturers didn’t bother prioritizing the ipv6 stack because carriers weren’t demanding it so HW had very immature and buggy ipv6 stacks which further prohibited ISPs from turning it on because it was another 1-3 purchase cycles before the stack actually worked correctly. And none of that solves the chicken/egg problem of the lack of eyeball supply / customer demand.

The complexity of IPv6 contributed to some of it. Carrier grade NAT did most of the harm though and that would have been a thing regardless.

Re: Tell HN: IPv6-only still pretty much unusable

#493

Post by Bluecobra » Thu, Dec 08, 2022, 3:47 AM UTC

therealmocker wrote: post #397

yesco wrote: post #122

Earlier quoted context omitted.

A confusing aspect of IPv6 is that it's actually a much simpler protocol than IPv4, you often end up assuming you need to configure a bunch of stuff that you really don't have to. The most common example would be NAT, despite the complexity it adds to IPv4, people often get comfortable with idea of setting up complex subnet hierarchies and feel lost when that all just disappears with IPv6. The key things to remember…

One thing I wish they had done with the much larger address space is make it easy for an individual to get their own block of IPv6 addresses. Letting enthusiasts experiment with their own address space seems like it would help with knowledge / adoption.

I’m a network engineer by trade and think that would be cool, but I don’t think it’s a great idea to have a bunch of amateurs all of a sudden participating in BGP for numerous reasons. It’s certainly possible for an individual to setup a LLC, get an allocation from ARIN + AS number, order a business ISP connection w/ BGP and get an adequate router. It’s a high barrier of entry and won’t be cheap. Making that easier will likely lead to more widespread BGP issues (intentional or unintentional), filling up router TCAMs with even more prefixes, etc.

There’s already communities out there for hobbyists to play with/learn BGP on private networks over VPN tunnels if you really want to.

Re: Tell HN: IPv6-only still pretty much unusable

#494

Post by jgsaau » Thu, Dec 08, 2022, 3:53 AM UTC

On the dark web IPV6 is seen as a way for hackers to hide amoungst the forest of trees. I can detail millions of IPV4 addresses that are not being used, some blocks with ISP / WISP that have never been allocated to a 'customer'

Re: Tell HN: IPv6-only still pretty much unusable

#495

Post by vlovich123 » Thu, Dec 08, 2022, 3:55 AM UTC

bumbledraven wrote: post #488

redox99 wrote: post #32

IPv6 has been one of the biggest failures in the last couple of decades. And I don't mean adoption, I mean the standard itself. If IPv6 were IPv4 with more octets, then we would all have been using it for like a decade. Yes, I understand it would still require some breaking changes, but it would have been a million times easier to upgrade, as it would be a kind of superset of IPv4 (1.2.3.4 can be referred as 0.0.0.0.…

djb proposed this back in 2002: https://cr.yp.to/djbdns/ipv6mess.html > How do we teach every client on the Internet to talk to servers on public IPv6 addresses [and vice versa]? > Answer: We go through every place that 4-byte IPv4 addresses appear, and allow 16-byte IPv6 addresses in the same place. > ... > Unfortunately, the straightforward transition plan described above does not work with the current IPv6 specifi…

That is the exact right reason, none of the other BS that’s been written (notice the lack of complaints about new IPv6 features). It’s purely about v4/v6 interop. I’m still not 100% sure how you would have solved some of these problems though. It’s easy to state that’s the problem. A lot harder to show how you have these things interconnecting seemlessly.

Re: Tell HN: IPv6-only still pretty much unusable

#496

Post by vlovich123 » Thu, Dec 08, 2022, 3:58 AM UTC

dqh wrote: post #474

redox99 wrote: post #32

IPv6 has been one of the biggest failures in the last couple of decades. And I don't mean adoption, I mean the standard itself. If IPv6 were IPv4 with more octets, then we would all have been using it for like a decade. Yes, I understand it would still require some breaking changes, but it would have been a million times easier to upgrade, as it would be a kind of superset of IPv4 (1.2.3.4 can be referred as 0.0.0.0.…

I am not a network engineer, but for about 20 years I have wondered why we didn't 'just' do something like: 1. Include an extra 32-bits of address information as an IP options header. Call it an IP4.4 packet. 2. (I think?) IP4.4 packets would therefore happily travel over existing IP4 infrastructure. 3. Each existing IP4 address becomes a potential IP4.4 network with 32-bits of address space behind it. IP4.4 aware ro…

What happens when your 4.4 packet hits a router box somewhere out there that doesn’t understand 4.4? Where’s it going to send that packet? To the wrong address (or potentially even create an infinite loop). Now what?

Re: Tell HN: IPv6-only still pretty much unusable

#497

Post by vlovich123 » Thu, Dec 08, 2022, 4:01 AM UTC

ipython wrote: post #466

zhoujianfu wrote: post #407

Earlier quoted context omitted.

I always thought to start they should have just allowed each octet two-ish more bits, so you could have 999.999.999.999. I know it’s the hackiest of all hacks, but it sure would have been an easy upgrade from the software perspective. And it would have given about a 256x increase in the number of ips. Which I kinda think actually might have served us for a long time.

And where do those two extra bits go? How do existing routers that don’t know anything about two extra bits route those packets? Here’s the ip packet header: https://commons.wikimedia.org/wiki/File:IPv4_Packet-en.svg

In this thread, lots of people seem to think in terms of 255.255.255.255 and fail to recognize the IP address is 32bits and the textual representation of 4 octets means very little.

But the confidence and armchair expertise offered… wow.

Re: Tell HN: IPv6-only still pretty much unusable

#498

Post by zajio1am » Thu, Dec 08, 2022, 4:02 AM UTC

vel0city wrote: post #152

lzaaz wrote: post #113

Earlier quoted context omitted.

It is a substitute to an actual firewall because I don't need a firewall since NAT makes all of my listening ports unavailable to my WAN.

Depending on the NAT implementation this can be incredibly naive. Many home routers will send ANY traffic incoming on a port to the NAT'd IP address, even if the sources don't line up. So say Alice is behind a crappy NAT and wants to talk to Bob. Alice's router opens a port on its edge, lets say 1234, and sends traffic to Bob on port 80. Let's say Charles knows Alice's IP address. Charles starts spamming Alice's rout…

> Alice's router is dumb. It sees traffic on port 1234, checks its NAT table, and sees that data is supposed to go to Alice.

While in principle that is possible, in practice almost all home routers are based on Linux, and Linux netfilter NAT implementation distinguish connections based on port and IP, not just port, so this would not work.

Re: Tell HN: IPv6-only still pretty much unusable

#499

Post by throwaway2037 » Thu, Dec 08, 2022, 4:13 AM UTC

nightfly wrote: post #323

throw0101a wrote: post #164

Earlier quoted context omitted.

> And regarding compatibility, with ipv4+ if you have a 0.0.0.0.x.x.x.x ip address you would be able to talk to both ipv4+ aware and legacy ipv4 devices natively without any tunneling (because you also own the legacy, non quad 0 ip address). This exists: > Addresses in this group consist of an 80-bit prefix of zeros, the next 16 bits are ones, and the remaining, least-significant 32 bits contain the IPv4 address. For…

We've tried to roll out IPv6 at my work, and after several years of it causing more issues than it help we turned it all off again... We're gonna get back to it again this year, but I can see many organizations just not doing that until absolutely forced.

Thank you to share a real world story. Failure is usually more interesting to study than success. Real question (no trolling): Is there any business value upgrading to IPv6 or is this a forced upgrade? I think that is number one reason that delays IPv6 upgrades: no business value (or so limited compared to cost of IPv6 impl).

Re: Tell HN: IPv6-only still pretty much unusable

#500

Post by [deleted] » Thu, Dec 08, 2022, 4:24 AM UTC

Arnavion wrote: post #320

cj wrote: post #178

Earlier quoted context omitted.

I have the technical ability to set up a well structured VPC in AWS with private/public subnets, but I wouldn't know where to start if asked to set up an ipv6-only network. Is the general model of public/private subnet still valid? Or are you saying in a ipv6-only world, there's no need for separate subnets? There's something about a server not being assigned an IP address at all that makes me sleep easy at night (in…

>Is the general model of public/private subnet still valid? Or are you saying in a ipv6-only world, there's no need for separate subnets? Define "public/private". Your server has an IPv6 address that is globally identifiable. Your gateway may not necessarily route traffic to it. >(in ipv4 world, you know that server is truly unreachable via public internet) You don't know that, because a port forward rule on the gate…

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