11 ms·

There are 3 problems with IPv6 - There is a lot in IPv6 that is different from IPv4. Ignoring if those changes are good or bad, it does make the transition har

by phicoh 8y ago

There are 3 problems with IPv6 - There is a lot in IPv6 that is different from IPv4. Ignoring if those changes are good or bad, it does make the transition harder. - IPv6 was promoted way before there was demand. To some extent it is good to prepare people (and vendors). But it does create the impression that IPv6 is a failure - Demand for IPv6 is highly asymmetrical. The party that is out of IPv4 addresses needs IPv6. But everyone who has enough IPv4 space has no reason to care. When IPv6 was first promoted, there basically was no IPv4 market. You would just go and get more IPv4 space when needed. For the last couple of years we now have a mature market for IPv4 addresses. It is possible to buy IPv4 addresses, but prices go up. At some point it becomes interesting to try to move traffic to IPv6.

zzzcpan 8y ago
> The party that is out of IPv4 addresses needs IPv6. That party is not an ISP though. An ISP is interested to provide IPv4 internet no matter whether there is IPv6 or there isn't.
hn_throwaway_99 8y ago
> For the last couple of years we now have a mature market for IPv4 addresses. Which highlights the utter failure of v6 - people are willing to pay for access to technology that v6 was supposed to make obsolete over a decade ago.
- phicoh 8y ago
  I disagree. You have to consider network effects. Even if IPv6 was completely perfect, switching on your own doesn't do any good. You need to get most of the network to switch to get the benefits. Given that there is always a cost to switching, people will consider switching when continuing on the old path will become more costly than switching.
  - nothrabannosir 8y ago
    >> ... the utter failure of v6. > Even if IPv6 was completely perfect... More specifically: "completely technologically perfect". Which is the point being made in this thread: the technical aspect is of only partial relevance. If IPv6 fails because of political problems, or "contextual ones" (like “we could make it technologically inferior but more readily backwards compatible; it would make it less awesome but easier for people to migrate”), then that is still "failure of IPv6". If IPv6 had been perfect, it would be fully backwards compatible, and there would be no market for IPv4 right now. Just because that isn't possible doesn't mean there isn't a middle ground.
    - phicoh 8y ago
      It is easy enough to criticize the IETF and the wider IPv6 community for the mistakes they made. But as far as I know, nobody came up with a credible protocol that is fully backward compatible with IPv4. So, you can ask the IETF to come up with a magically protocol that has longer addresses and is still backward compatible with IPv4. But they are only human. So that kind of magic is not going to happen.
      - Aeolun 8y ago
        Wouldn’t a predefined mask for IPv6 addresses do exactly that? The last 32 bytes of the address could easily be an IPv4 address I should think.
        Dylan16807 8y ago
        A mask like 0000:0000:0000:0000:0000:ffff:xxxx:xxxx/96?
        Dagger2 8y ago
        Nope, because: - you would need to restrict yourself to an extremely tiny fraction of the v6 space that's the same size as the v4 space - you couldn't use any IPs that correspond to in-use v4 IPs because they would overlap - you couldn't use any IPs that correspond to unusable v4 IPs, for the same reasons you can't use them in v4 - you'd have to talk a protocol that looks the same as v4 on the wire, because otherwise v4 hosts won't be able to handle it You know what we call that? We call it IPv4.
geofft 8y ago
Why is IPv6 more attractive for address exhaustion than IPv4 NAT? As the article argues, you can't run IPv6-only. You need some strategy to reach IPv4 services on the internet because the internet is IPv4. That answer is going to be either publicly routable IPv4, IPv4-to-IPv4 NAT, or IPv4-to-IPv6 NAT. If you do the latter (or if you do dual stack) you can route directly to other IPv6 hosts without NAT - but what's the benefit? Are there systems of communication between parties on the public internet that can guarantee native IPv6 on both ends, don't want to use IPv4 NAT, and don't want to set up a point-to-point VPN? (I am actually okay with IPv6 ULAs for private addressing on private VPNs to avoid RFC 1918 collisions/exhaustion, but that also saves you a lot of the complexity of IPv6 deployment because you don't need any network device support, you generally get address assignments from your VPN layer and don't need to think about SLAAC or DHCPv6 or anything, etc. And it's unrelated to public IPv4 exhaustion.)
- wmf 8y ago
  Native IPv6 is cheaper than NAT at ISP scale. If a consumer ISP adopts IPv6, half of their traffic will be native IPv6 without NAT. If the ISP tries to do NAT444 then all of their traffic will be NATed, requiring more equipment.
- phicoh 8y ago
  There are a couple of reasons: - There are limits to how many devices you can put behind a single IPv4 address. There is the case of Belgium where law enforcement asked ISPs to limit CGNAT to 16 customers per IPv4 address. Obviously for law enforcement, if an address is shared between multiple customers it makes investigations harder. - A second problem it that you may lose geographical resolution if customers for a wide area share a pool of addresses. For some ad placement you really want to know where addresses are. - But the bigger problem is that network speeds keep growing. Compared to an IPv6 router, boxes that can do NAT at a large scale and high speed are quite expensive. So an ISP has an incentive to move traffic volume to IPv6. Relatively low volume oddball sites can go over the NAT box.
  - geofft 8y ago
    Do these arguments not apply to IPv6 customers speaking to legacy IPv4 sites? They also have to go through IPv4 NAT, it's just that the NAT is converting it to a public IPv6 address instead of a CGNAT IPv4 one. Wouldn't law enforcement and ad targeting be equally unhappy by piles of IPv6 users being converted to the same IPv4 address? If enough of the Internet is running IPv6 that you save significantly on performance by bypassing NAT for IPv6 sites only, that seems worthwhile, sure. But also I'd intuitively find that surprising, at least at present - maybe my intuitions are just wrong about how much IPv6 there is.
gregmac 8y ago
- No transition or migration design. It seems like IPv6 was designed as if it was being built instead of building IPv4, and didn't consider how the move would happen beyond something like "everyone run dual-stack IPv4/IPv6, and once that's at 100% we'll turn off IPv4." This results in a stale-mate of sorts: As a server operator, as long as you have IPv4-only clients, you need an IPv4 address. There are no [1] IPv6-only clients, so implementing IPv6 at all is a lot of work with no tangible benefits for the next x years [2]. As a client, you can't go IPv6-only without losing access to the IPv4-only services. There are no[1] IPv6-only servers, so implementing IPv6 at all is a bunch of work with no real benefits for the next x years[2] [1] no meaning a tiny fraction that rounds to 0% [2] x being the number of years before there's a significant number of IPv6-only servers or users.
- mikekchar 8y ago
  This is literally my problem with upgrading to IPv6 currently. And at the cost of potentially embarrassing myself, I haven't really looked into what the potential problems are going to be (and I'm embarrassed to ask :-) ). My ISP will happily switch me from IPv4 to IPv6 but I've got absolutely no idea what the potential problems are. This has put the task into a near perpetual, "I'll look at that when I'm not so busy". I'm sure I'm not alone in this...
  - pas 8y ago
    demand dual stack. nothing else really works. sure, we can simply stay on v4 and encapsulate everything into UDP and use vhost or other names and simply treat v4 address + ports as the solution. economically both are costs of growing the internet. (any solution requires a lot of application changes anyhow, v6 is simpler, but requires ISP buy in, so what app devs can do?)
- phicoh 8y ago
  To some extent this is unavoidable. Anything that is 'IPv4-like with larger addresses' is very much incompatible with any IPv4 equipment or setup at the edge. You could design something where the IPv4 could be left unchanged in the core of the Internet. But the core of the Internet has supported IPv6 for a long time, it is the edges where the problems are. Just something as simple as writing an address to a log file would fail if addresses suddenly became bigger.
4bpp 8y ago
More issues with IPv6 that are relevant for me as a techie: - Memorising an IPv4 address is about as easy as memorising a phone number, which is to say, fairly easy. I remember the iPv4 addresses of both my rental servers, every device on my home LAN, a bunch of public DNS servers if things go wrong, ...; there's no way I'm going to be able to do that for IPv6. - At least last time I tested it (more than 10 years ago now), the greater length of IPv6 headers had a quite measurable adverse impact on transmission latency of small packets (online gaming, remote shell...) - Why do people keep treating "you get your own unique IP address when browsing" as if it were an advantage? The way I see it, NAT and IP address reuse (especially together with some European countries' laws stipulating the address->identity mapping must be deleted within some time period) are the currently most widely rolled out privacy technology. Somewhere downthread, they talk about how Belgian police is trying to prevent ISPs from putting more than 16 customers behind the same internet address. Since I can hardly say everything I do on the internet is perfectly legal, what's bad for Belgian police is probably good for me.
- z3phyr 8y ago
  > Why do people keep treating "you get your own unique IP address when browsing" as if it were an advantage? The original tenet of the internet pretty much hinged on the idea that every person with a computer can host/self-publish information as well as consume other people's information in a distributed way. They will not have to depend on a centralized publishing authority. I think v6 could have enabled this
- jjeaff 8y ago
  I have no real first hand knowledge of this, but I have wondered if part of the reluctance of ipv6 is the fact that many of the "powers that be" use ip addresses to identify and group traffic and other activity from multiple devices. They also use ip addresses to block scrapers (both Google and Amazon do this heavily). With ipv6, an IP address can be completely disposable. You could scrape Google search results all day long and use a different address for each call. Heck, you could completely proxy search results in real time and create your own search engine, secretly using Google as your backend while injecting your own ads.
bsder 8y ago
You missed: - No real competition in ISPs If you had a national ISP in the US who ran IPv6 with end-to-end connectivity without NATs, a killer app would move to it and then drag all the other ISPs onto IPv6.
- selectodude 8y ago
  Comcast runs native IPv6, along with Verizon Wireless and T-Mobile. A full 40 percent of US traffic to Google is over v6.
vbezhenar 8y ago
I never truly delved into low level networking, but I generally got a grasp for IPv4, I can setup simple networks and I think that I understand what's going on on every level. Now despite the fact that I tried to understand IPv6 multiple times, I failed miserably all the time. I tried to setup IPv6-over-IPv4 OpenVPN, it did not work despite all efforts. IPv6 is just too complex. At this point I wish that IPv6 would be just IPv4 with 16-byte address (or better 8-byte, because that's really enough for everyone and another 8 bytes I have no idea who really need that, and our computers work natively with 8 bytes), keeping all concepts the same. Now I'm aggressively against any IPv6 and I'll do only the minimal amount of work to support IPv6 clients for my services while using IPv4 for my own infrastructure everywhere.
- phicoh 8y ago
  By and large IPv6 is very similar to IPv4, but of course without NAT. For example, at my home I get a /48 prefix from my ISP over DHCPv6 (over PPPoE). Then I assign /64 prefixes to my subnets. After that, hosts pick up addresses using SLAAC. Obviously, VPNs are more complex, but that's not the fault of IPv6.
- ivlad 8y ago
  Well, that's pretty childish of you. "I didn't understand it, so I will be bitching how bad it is." If you think, you understand IPv4 well enough, this book will explain the differences and why certain decisions were made when IPv6 was designed: https://sites.google.com/site/yartikhiy/home/ipv6book https://sites.google.com/site/yartikhiy/home/ipv6book
- betterunix2 8y ago
  IPv6 is in no way more complicated than IPv4, especially if you include all the things you need to make IPv4 work in practice (NAT, techniques for dealing with NAT, etc.). IPv6 is different which is probably why you are having trouble: you wanted something just like IPv4 but with larger addresses, but that is not IPv6. For me the key to understanding IPv6 was to view it as something totally different, and not try to map my understanding of IPv4 onto IPv6. Now I am aggressively against IPv4, because over and over I see problems resulting from NAT, or collisions in private address ranges on two LANs, or broken path MTU discovery, etc. The only arguments for IPv4 are economic or political; at this point the technical debate is over and IPv6 is a clear winner (the majority of technical problems in IPv6 deployment are related to compatibility with IPv4).
mncharity 8y ago
> IPv6 was promoted way before there was demand. No? My recollection is the original primary objective of IP Next was to prevent the net's flat address space from collapsing into NATed fragments. The need was immediate and pressing. We failed. Now we all live in what was feared - a post-collapse wasteland of centralized systems.
burtonator 8y ago
> - Demand for IPv6 is highly asymmetrical. The party that is out of IPv4 addresses needs IPv6. But everyone who has enough IPv4 space has no reason to care. We might need some way to force them... Google has done a lot of good by changing functionality for SEO + chrome by giving warning or giving PR boost if your site has a certain feature. They should consider prioritizing sites that have both IPv4 and IPv6 and also warn users in the browser if the site does not have IPv6. It's a legit warning too: "Warning! This site may not work on some networks!"

by phicoh 8y ago

zzzcpan 8y ago

> The party that is out of IPv4 addresses needs IPv6. That party is not an ISP though. An ISP is interested to provide IPv4 internet no matter whether there is IPv6 or there isn't.

hn_throwaway_99 8y ago

> For the last couple of years we now have a mature market for IPv4 addresses. Which highlights the utter failure of v6 - people are willing to pay for access to technology that v6 was supposed to make obsolete over a decade ago.

phicoh 8y ago
I disagree. You have to consider network effects. Even if IPv6 was completely perfect, switching on your own doesn't do any good. You need to get most of the network to switch to get the benefits. Given that there is always a cost to switching, people will consider switching when continuing on the old path will become more costly than switching.
- nothrabannosir 8y ago
  >> ... the utter failure of v6. > Even if IPv6 was completely perfect... More specifically: "completely technologically perfect". Which is the point being made in this thread: the technical aspect is of only partial relevance. If IPv6 fails because of political problems, or "contextual ones" (like “we could make it technologically inferior but more readily backwards compatible; it would make it less awesome but easier for people to migrate”), then that is still "failure of IPv6". If IPv6 had been perfect, it would be fully backwards compatible, and there would be no market for IPv4 right now. Just because that isn't possible doesn't mean there isn't a middle ground.
  - phicoh 8y ago
    It is easy enough to criticize the IETF and the wider IPv6 community for the mistakes they made. But as far as I know, nobody came up with a credible protocol that is fully backward compatible with IPv4. So, you can ask the IETF to come up with a magically protocol that has longer addresses and is still backward compatible with IPv4. But they are only human. So that kind of magic is not going to happen.
    - Aeolun 8y ago
      Wouldn’t a predefined mask for IPv6 addresses do exactly that? The last 32 bytes of the address could easily be an IPv4 address I should think.
      - Dylan16807 8y ago
        A mask like 0000:0000:0000:0000:0000:ffff:xxxx:xxxx/96?
      - Dagger2 8y ago
        Nope, because: - you would need to restrict yourself to an extremely tiny fraction of the v6 space that's the same size as the v4 space - you couldn't use any IPs that correspond to in-use v4 IPs because they would overlap - you couldn't use any IPs that correspond to unusable v4 IPs, for the same reasons you can't use them in v4 - you'd have to talk a protocol that looks the same as v4 on the wire, because otherwise v4 hosts won't be able to handle it You know what we call that? We call it IPv4.

geofft 8y ago

Why is IPv6 more attractive for address exhaustion than IPv4 NAT? As the article argues, you can't run IPv6-only. You need some strategy to reach IPv4 services on the internet because the internet is IPv4. That answer is going to be either publicly routable IPv4, IPv4-to-IPv4 NAT, or IPv4-to-IPv6 NAT. If you do the latter (or if you do dual stack) you can route directly to other IPv6 hosts without NAT - but what's the benefit? Are there systems of communication between parties on the public internet that can guarantee native IPv6 on both ends, don't want to use IPv4 NAT, and don't want to set up a point-to-point VPN? (I am actually okay with IPv6 ULAs for private addressing on private VPNs to avoid RFC 1918 collisions/exhaustion, but that also saves you a lot of the complexity of IPv6 deployment because you don't need any network device support, you generally get address assignments from your VPN layer and don't need to think about SLAAC or DHCPv6 or anything, etc. And it's unrelated to public IPv4 exhaustion.)

wmf 8y ago
Native IPv6 is cheaper than NAT at ISP scale. If a consumer ISP adopts IPv6, half of their traffic will be native IPv6 without NAT. If the ISP tries to do NAT444 then all of their traffic will be NATed, requiring more equipment.
phicoh 8y ago
There are a couple of reasons: - There are limits to how many devices you can put behind a single IPv4 address. There is the case of Belgium where law enforcement asked ISPs to limit CGNAT to 16 customers per IPv4 address. Obviously for law enforcement, if an address is shared between multiple customers it makes investigations harder. - A second problem it that you may lose geographical resolution if customers for a wide area share a pool of addresses. For some ad placement you really want to know where addresses are. - But the bigger problem is that network speeds keep growing. Compared to an IPv6 router, boxes that can do NAT at a large scale and high speed are quite expensive. So an ISP has an incentive to move traffic volume to IPv6. Relatively low volume oddball sites can go over the NAT box.
- geofft 8y ago
  Do these arguments not apply to IPv6 customers speaking to legacy IPv4 sites? They also have to go through IPv4 NAT, it's just that the NAT is converting it to a public IPv6 address instead of a CGNAT IPv4 one. Wouldn't law enforcement and ad targeting be equally unhappy by piles of IPv6 users being converted to the same IPv4 address? If enough of the Internet is running IPv6 that you save significantly on performance by bypassing NAT for IPv6 sites only, that seems worthwhile, sure. But also I'd intuitively find that surprising, at least at present - maybe my intuitions are just wrong about how much IPv6 there is.

gregmac 8y ago

- No transition or migration design. It seems like IPv6 was designed as if it was being built instead of building IPv4, and didn't consider how the move would happen beyond something like "everyone run dual-stack IPv4/IPv6, and once that's at 100% we'll turn off IPv4." This results in a stale-mate of sorts: As a server operator, as long as you have IPv4-only clients, you need an IPv4 address. There are no [1] IPv6-only clients, so implementing IPv6 at all is a lot of work with no tangible benefits for the next x years [2]. As a client, you can't go IPv6-only without losing access to the IPv4-only services. There are no[1] IPv6-only servers, so implementing IPv6 at all is a bunch of work with no real benefits for the next x years[2] [1] no meaning a tiny fraction that rounds to 0% [2] x being the number of years before there's a significant number of IPv6-only servers or users.

mikekchar 8y ago
This is literally my problem with upgrading to IPv6 currently. And at the cost of potentially embarrassing myself, I haven't really looked into what the potential problems are going to be (and I'm embarrassed to ask :-) ). My ISP will happily switch me from IPv4 to IPv6 but I've got absolutely no idea what the potential problems are. This has put the task into a near perpetual, "I'll look at that when I'm not so busy". I'm sure I'm not alone in this...
- pas 8y ago
  demand dual stack. nothing else really works. sure, we can simply stay on v4 and encapsulate everything into UDP and use vhost or other names and simply treat v4 address + ports as the solution. economically both are costs of growing the internet. (any solution requires a lot of application changes anyhow, v6 is simpler, but requires ISP buy in, so what app devs can do?)
phicoh 8y ago
To some extent this is unavoidable. Anything that is 'IPv4-like with larger addresses' is very much incompatible with any IPv4 equipment or setup at the edge. You could design something where the IPv4 could be left unchanged in the core of the Internet. But the core of the Internet has supported IPv6 for a long time, it is the edges where the problems are. Just something as simple as writing an address to a log file would fail if addresses suddenly became bigger.

4bpp 8y ago

More issues with IPv6 that are relevant for me as a techie: - Memorising an IPv4 address is about as easy as memorising a phone number, which is to say, fairly easy. I remember the iPv4 addresses of both my rental servers, every device on my home LAN, a bunch of public DNS servers if things go wrong, ...; there's no way I'm going to be able to do that for IPv6. - At least last time I tested it (more than 10 years ago now), the greater length of IPv6 headers had a quite measurable adverse impact on transmission latency of small packets (online gaming, remote shell...) - Why do people keep treating "you get your own unique IP address when browsing" as if it were an advantage? The way I see it, NAT and IP address reuse (especially together with some European countries' laws stipulating the address->identity mapping must be deleted within some time period) are the currently most widely rolled out privacy technology. Somewhere downthread, they talk about how Belgian police is trying to prevent ISPs from putting more than 16 customers behind the same internet address. Since I can hardly say everything I do on the internet is perfectly legal, what's bad for Belgian police is probably good for me.

z3phyr 8y ago
> Why do people keep treating "you get your own unique IP address when browsing" as if it were an advantage? The original tenet of the internet pretty much hinged on the idea that every person with a computer can host/self-publish information as well as consume other people's information in a distributed way. They will not have to depend on a centralized publishing authority. I think v6 could have enabled this
jjeaff 8y ago
I have no real first hand knowledge of this, but I have wondered if part of the reluctance of ipv6 is the fact that many of the "powers that be" use ip addresses to identify and group traffic and other activity from multiple devices. They also use ip addresses to block scrapers (both Google and Amazon do this heavily). With ipv6, an IP address can be completely disposable. You could scrape Google search results all day long and use a different address for each call. Heck, you could completely proxy search results in real time and create your own search engine, secretly using Google as your backend while injecting your own ads.

bsder 8y ago

You missed: - No real competition in ISPs If you had a national ISP in the US who ran IPv6 with end-to-end connectivity without NATs, a killer app would move to it and then drag all the other ISPs onto IPv6.

selectodude 8y ago
Comcast runs native IPv6, along with Verizon Wireless and T-Mobile. A full 40 percent of US traffic to Google is over v6.

vbezhenar 8y ago

I never truly delved into low level networking, but I generally got a grasp for IPv4, I can setup simple networks and I think that I understand what's going on on every level. Now despite the fact that I tried to understand IPv6 multiple times, I failed miserably all the time. I tried to setup IPv6-over-IPv4 OpenVPN, it did not work despite all efforts. IPv6 is just too complex. At this point I wish that IPv6 would be just IPv4 with 16-byte address (or better 8-byte, because that's really enough for everyone and another 8 bytes I have no idea who really need that, and our computers work natively with 8 bytes), keeping all concepts the same. Now I'm aggressively against any IPv6 and I'll do only the minimal amount of work to support IPv6 clients for my services while using IPv4 for my own infrastructure everywhere.

phicoh 8y ago
By and large IPv6 is very similar to IPv4, but of course without NAT. For example, at my home I get a /48 prefix from my ISP over DHCPv6 (over PPPoE). Then I assign /64 prefixes to my subnets. After that, hosts pick up addresses using SLAAC. Obviously, VPNs are more complex, but that's not the fault of IPv6.
ivlad 8y ago
Well, that's pretty childish of you. "I didn't understand it, so I will be bitching how bad it is." If you think, you understand IPv4 well enough, this book will explain the differences and why certain decisions were made when IPv6 was designed: https://sites.google.com/site/yartikhiy/home/ipv6book https://sites.google.com/site/yartikhiy/home/ipv6book
betterunix2 8y ago
IPv6 is in no way more complicated than IPv4, especially if you include all the things you need to make IPv4 work in practice (NAT, techniques for dealing with NAT, etc.). IPv6 is different which is probably why you are having trouble: you wanted something just like IPv4 but with larger addresses, but that is not IPv6. For me the key to understanding IPv6 was to view it as something totally different, and not try to map my understanding of IPv4 onto IPv6. Now I am aggressively against IPv4, because over and over I see problems resulting from NAT, or collisions in private address ranges on two LANs, or broken path MTU discovery, etc. The only arguments for IPv4 are economic or political; at this point the technical debate is over and IPv6 is a clear winner (the majority of technical problems in IPv6 deployment are related to compatibility with IPv4).

mncharity 8y ago

> IPv6 was promoted way before there was demand. No? My recollection is the original primary objective of IP Next was to prevent the net's flat address space from collapsing into NATed fragments. The need was immediate and pressing. We failed. Now we all live in what was feared - a post-collapse wasteland of centralized systems.

burtonator 8y ago

> - Demand for IPv6 is highly asymmetrical. The party that is out of IPv4 addresses needs IPv6. But everyone who has enough IPv4 space has no reason to care. We might need some way to force them... Google has done a lot of good by changing functionality for SEO + chrome by giving warning or giving PR boost if your site has a certain feature. They should consider prioritizing sites that have both IPv4 and IPv6 and also warn users in the browser if the site does not have IPv6. It's a legit warning too: "Warning! This site may not work on some networks!"