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IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

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Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#51

Post by jiggawatts »

hansel_der wrote: post #37
jiggawatts wrote: post #30

Earlier quoted context omitted.

The only "problem" here that is caused by IPv6 is the SD-WAN / multi-provider scenario. Even that is solvable. There are so many IPv6 addresses that your local router can have a unique routable range that it can hand out to the local network, "masking" the external internet provider addresses in the same way that IPv4 routing does it. That's not NAT, that's just routing. E.g. I have a customer that uses a non-RFC1918…

y u so mad? > Literally counterproductive in the case of Azure, where turning on IPv6 anywhere will break unrelated IPv4 functionality! not just on azure; smartphones seem to be the only environment were v6 is doing its job (lots of smartphones need lots of addresses. ipv6 has a lot of addresses, problem solved) and i guess it's because they are most user-centric client-device imaginable, the actual users don't care…

I'm mad because network "engineers" use that word without realising what it entails to earn that title.

The painting has been on the wall for decades. IPv4 exhaustion was predicted to the week.

Did anyone do anything about it? No.

There are people talking about how Kubernetes is the "future" on this very forum, yet it simply does not work with IPv6. Instead, it uses NAT and RFC1918 ranges... but you've got to be careful not to accidentally overlap those subnets with the rest of your network!

I have a customer that screwed this up and now they're facing a rebuild of 3 out of 4 of their clusters. Fun times.

I have another customer undergoing mergers, where renumbering their IPv4 RFC1918 ranges is going to cost them on the order of $10M.

IPv4 is the legacy, and its costing real money to keep it going decades after its expiry.

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#52

Post by benttoothpaste »

RedShift1 wrote: post #20
bushbaba wrote: post #4

Earlier quoted context omitted.

I’ve often wondered if ipv6s less human readable addresses is the primary cause. I dread using and interacting with ipv6, compared to ipv4. Sure ipv6 solves a lot of scaling challenges, but it is so much harder to grock at first glance.

Many of the "IPv6-isms" come from the fact that renumbering networks is a big PITA and so IPv6 was built with the pipe dream of "change the config on the router and the entire network renumbers itself", like the flick of a switch. It was optimised for the least used case. IMO they should have just increased the address bit size to 128 and be done with it. One of my own annoyances is the fact that local subnets have t…

It’s even worse - many home routers will simply disable ipv6 if the ISP gives /64.

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#53

Post by hansel_der »

jiggawatts wrote: post #51
hansel_der wrote: post #37

Earlier quoted context omitted.

y u so mad? > Literally counterproductive in the case of Azure, where turning on IPv6 anywhere will break unrelated IPv4 functionality! not just on azure; smartphones seem to be the only environment were v6 is doing its job (lots of smartphones need lots of addresses. ipv6 has a lot of addresses, problem solved) and i guess it's because they are most user-centric client-device imaginable, the actual users don't care…

I'm mad because network "engineers" use that word without realising what it entails to earn that title. The painting has been on the wall for decades. IPv4 exhaustion was predicted to the week . Did anyone do anything about it? No. There are people talking about how Kubernetes is the "future" on this very forum, yet it simply does not work with IPv6. Instead, it uses NAT and RFC1918 ranges... but you've got to be car…

> I have another customer undergoing mergers, where renumbering their IPv4 RFC1918 ranges is going to cost them on the order of $10M.

i suppose that is way less than what a switch to v6 would cost?

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#54

Post by soneil »

usr1106 wrote: post #24
bushbaba wrote: post #4

Earlier quoted context omitted.

I’ve often wondered if ipv6s less human readable addresses is the primary cause. I dread using and interacting with ipv6, compared to ipv4. Sure ipv6 solves a lot of scaling challenges, but it is so much harder to grock at first glance.

So did 64 bit CPU adoption get delayed because addresses are hard to read compared to 32 bit addresses? Maybe not so much... But the argument might still hold. If 80% of average network admins decide to hate IPv6 because they can no longer remember IP addresses of several machines and subnets by heart that might hinder adoption. Most of them are not daily affected by the fact that the world has run out of IPv4 addres…

Remembering your own machines really isn't the problem people think it is.

If I ask you what 192.168.1.1 is, you're probably going to guess it's a router/gateway. There is absolutely no reason for it to be, it's merely an accepted convention that the lowest-numbered host is the gateway.

There's absolutely nothing stopping you doing the same in ipv6. If you need to be able to remember where your gateway is, put it on 2001:db8::1. The problem isn't that they're long, it's that for some reason we assume we have to remember dynamically assigned addresses. Any address you have to memorise shouldn't be dynamically assigned, whether it's v4 or v6.

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#55

Post by jiggawatts »

hansel_der wrote: post #53
jiggawatts wrote: post #51

Earlier quoted context omitted.

I'm mad because network "engineers" use that word without realising what it entails to earn that title. The painting has been on the wall for decades. IPv4 exhaustion was predicted to the week . Did anyone do anything about it? No. There are people talking about how Kubernetes is the "future" on this very forum, yet it simply does not work with IPv6. Instead, it uses NAT and RFC1918 ranges... but you've got to be car…

> I have another customer undergoing mergers, where renumbering their IPv4 RFC1918 ranges is going to cost them on the order of $10M. i suppose that is way less than what a switch to v6 would cost?

Precisely.

And why should IPv6 be expensive?

Is it because we still tolerate vendors throwing up software that merely pretends to be IPv6 capable?

Or because IPv6 is magically harder than IPv4 despite being nearly identical?

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#56

Post by yardstick »

ivlad wrote: post #35
yardstick wrote: post #28

Taken from a previous comment I’ve made re IPv6: IPv6 is fundamentally not ready for real world use within small/medium businesses and homes IMO. At least not without NAT. Why? - Can’t just simply put one IPv6 router/firewall behind another. Not all IPv6 routers support DHCP-PD, and even if they did, you could have 2-3-4 levels of routers/firewalls at a business. I’m not making this up- retail/gas/food industries oft…

Before I start I must say, I built IPv6 only datacenters and enterprise networks. I am saying from experience. > Can’t just simply put one IPv6 router/firewall behind another. Not all IPv6 routers support DHCP-PD, and even if they did, you could have 2-3-4 levels of routers/firewalls at a business. You cannot do this with IPv4 either. Routing has to work. It works for both IPv4 and In But if you are saying, you add 2…

Datacenter networks are an entirely different beast to SME and SOHO business networks. You don’t get the same budget for nice equipment, nor dedicated IT persons to run it, nor any remotely technical people on the ISP side to help you. SME and SOHO are very price conscious too. Think low margin retail and petroleum and fastfood.

> You cannot do this with IPv4 either. Routing has to work. It works for both IPv4 and In But if you are saying, you add 2-3-4 layers of NAT, this is just crazy.

Yes, you literally can stack a dozen commercial IPv4 firewall/routers behind each others networks and a PC plugged into the very last one will have no problems access Google on the browser. Because of NAT, which all IPv4 capable personal/SOHO/SME routers do by default.

Sure, VoIP may not work, but actually chances are it will because the VoIP service will be NAT-free via VPN to the provider.

And in this retail/petro/fastfood environment things like p2p file sharing are irrelevant and not required. All traffic is either to websites or to corporate systems across VPNs where NAT is not present or easily managed.

> By sending RA and expiring the old prefix on the failover. I admit, this is not an obvious solution and it may not be suitable for some edge cases.

It’s a slow failover by comparison to IPv4 methods. Too slow for some common use cases in industries I deal with. It also doesn’t allow for load balancing across links (eg route all important traffic out link 1 by default and all backup uploads out link 2 by default).

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#57

Post by yardstick »

rnhmjoj wrote: post #34
yardstick wrote: post #28

Taken from a previous comment I’ve made re IPv6: IPv6 is fundamentally not ready for real world use within small/medium businesses and homes IMO. At least not without NAT. Why? - Can’t just simply put one IPv6 router/firewall behind another. Not all IPv6 routers support DHCP-PD, and even if they did, you could have 2-3-4 levels of routers/firewalls at a business. I’m not making this up- retail/gas/food industries oft…

> Not all IPv6 routers support DHCP-PD I my experience, they all did. I'm not even sure how you could possibly deploy IPv6 without it, manually handing out prefixes? > you could have 2-3-4 levels of routers/firewalls at a business. It seems just a bad design, but I still don't see how IPv6 would not allow it. > Why? Not all ISPs give static IPv6 prefixes, not all PCs/servers/devices support DHCP6 for static leases, a…

Sorry I could have stated the DHCP-PD issue more clearly. Comcast doesn’t support it. [1]

> I honestly don't understand the difference with IPv4. You can have multiple addresses and do load balancing on the router with both.

A PC cannot easily have 2 different IPv4 subnets in the same NIC, which is what IPv6 permits with RA. Even if a PC did have 2 networks, how does the router tell the PC to use fibre for everything except backups, and cable for backups, and cellular only if the others fail? These decisions are best made by the router, not an arbitrary client device connected behind it. With IPv6 and no NAT, how does the client PC know what IP to use as its source at any given time? Yes NAT66 works- and for a very very long time the IPv6 community has resisted any NAT, which has resulted in poor NAT support in IPv6 stacks across many vendors.

> Wrong! Everyone needs routable addresses, even if they don't know it because they need VoIP, video calls on webRTC, FTP, p2p file sharing, online games, etc. All of these barely manage to work in a NAT by using workarounds like ALGs, UpnP, NAT-PMP, relay servers and other atrocities that greatly complicate the network design and are a security nightmare.

I didn’t say a routable IP isn’t required. I said a dedicated unique public IP is not required.

A gas station or fast food business doesn’t need online games or p2p file sharing. Their VoIP is done over VPN or uses NAT ALG in the firewall. Their web browser and payment systems are happy with a NAT’d IP on a LAN behind their router (which may or may not have a public static IPv4).

1. https://forums.businesshelp.comcast.com/conversations/ipv6/i...

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#58

Post by yardstick »

jiggawatts wrote: post #55
hansel_der wrote: post #53

Earlier quoted context omitted.

> I have another customer undergoing mergers, where renumbering their IPv4 RFC1918 ranges is going to cost them on the order of $10M. i suppose that is way less than what a switch to v6 would cost?

Precisely. And why should IPv6 be expensive? Is it because we still tolerate vendors throwing up software that merely pretends to be IPv6 capable? Or because IPv6 is magically harder than IPv4 despite being nearly identical?

IPv6 should have supported NAT like IPv4, not dragged its heels by begrudgingly implementing it years/decades later (and still not all support IPv6 NAT so the problem isn’t yet solved).

NAT, as much as you hate it, makes deployments easier and quicker and simpler for your average business. I don’t have to worry about BGP, or if my ISP has given me a /64 only or can they do a /60 or /48.

A gradual migration would have allowed both types of approaches to be used. Some would start with IPv6 using NAT, and other more switched on orgs could go straight away with NAT-free IPv6 networks. And lets face it, this has been a very gradual 20 years migration…

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#59

Post by usr1106 »

hansel_der wrote: post #42
usr1106 wrote: post #29

Earlier quoted context omitted.

Static IPv6 are rare by default because computers for end users should use IPv6 privacy extensions. In Ubuntu 16.04 LTS timeframe privacy extension was still broken a bit, so it did not work on every network adapter. Nowadays it just works, unless a crazy network gives you only /128. I have no idea about Windows and MacOS.

> unless a crazy network gives you only /128 like the incumbant cable network in germany (vodafone) ...

What? Germany is one of the most privacy-aware countries. So people should make some noise. Of course internet is still a bit new for all of us as the still-chancellor noted to too long ago... So technical incompetence does not surprise me. Vodafone prefers to make headlines with criminal sales practices.

Re: IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition

#60

Post by magicalhippo »

soneil wrote: post #54
usr1106 wrote: post #24

Earlier quoted context omitted.

So did 64 bit CPU adoption get delayed because addresses are hard to read compared to 32 bit addresses? Maybe not so much... But the argument might still hold. If 80% of average network admins decide to hate IPv6 because they can no longer remember IP addresses of several machines and subnets by heart that might hinder adoption. Most of them are not daily affected by the fact that the world has run out of IPv4 addres…

Remembering your own machines really isn't the problem people think it is. If I ask you what 192.168.1.1 is, you're probably going to guess it's a router/gateway. There is absolutely no reason for it to be, it's merely an accepted convention that the lowest-numbered host is the gateway. There's absolutely nothing stopping you doing the same in ipv6. If you need to be able to remember where your gateway is, put it on…

> put it on 2001:db8::1

Except my prefix is a hell of a lot longer than that...

And it's not my choice that it changes every now and then (at least once a month).

That said, I use DynDNS for IPv4 too, but it's easier since I only need to configure it for the router, but for IPv6 each machine I want to access needs it's own record.

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