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

https://www.ciscopress.com/store/ipv6-fundamentals-a-straightforward-approach-to-understanding-9780134670607

by teleforce • 5 years ago

53 62 5 years ago

ciscopress.com

woleium• 5 years ago

I first learned ipv6 22 years ago when I did my CCNP. Since then we've been two years away from migration every year.

betaby• 5 years ago

Close to 90% mobile phones in USA/Canada have IPv6 connectivity for about 5 years.

bikingbismuth• 5 years ago

My home ISP gives me an IPv6 address as well. Much of the internal infra that I use at work has AAAA records in our local DNS.

I feel comfortable saying IPv6 is here.

bushbaba• 5 years ago

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.

ashton314• 5 years ago

Address abbreviation helps a bunch. IPv6 (not an expert, but I’m in a class right now!) suffers from severe 2nd system syndrome: it overhauls DHCP in a totally convoluted way, overhauls so much of how the IP layer works, etc. It really is a mess.

ospray• 5 years ago

For all of it's faults Port Address Translation (NAT) sure has a way of making the address size more manageable.

jml7c52• 5 years ago

It's a silly bikeshed, but I wish they'd gone for hyphens as separators rather than colons. There's something about

    [abcd-ef12-3456-7890-abcd-ef12-3456-7890]

that's nicer to read than

    [abcd:ef12:3456:7890:abcd:ef12:3456:7890]

RedShift1• 5 years ago

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 to be /64's (you can make smaller subnets but it breaks certain things) and ISP's are supposed to deliver a /48 or /56 to subscribers but some ISP's will only hand one /64. So if you want to create 2 separate networks in your home you're screwed.

usr11066• 5 years ago

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 addresses. And NAT works well enough for most of them, many are even convinced it gives them security.

rjsw• 5 years ago

I have had native IPv6 from my ISP for 11 years now.

pvtmert• 5 years ago

Meanwhile, entire countries missing it today...

harshreality• 5 years ago

Over 30% global adoption for google users, to the extent of having a public ipv6 address and using ipv6 preferentially:

https://www.google.com/intl/en/ipv6/statistics.html

usr11066• 5 years ago

If you watch the graph in smaller time scale you see adoption is higher on weekends than on weekdays. I guess that means consumers using Google and similar from their mobile phones have a high rate of adoption. They did not do it themselves. While the average medium (and why not big) company IT department has not started to do anything and is IPv4 only. Seen in the graph when people work Monday to Friday and especially around Christmas.

Scott_Sanderson• 5 years ago

Both of my ISPs offer IPv6 gateways. I set them up and visited several IP6 websites.

I crypto exchange I use frequently, Bittrex, allows to whitelist an IP address. Since I have a static IPv4, I did so. Problem is, my request to bittrex always goes out the IP6 gateway and Bittrex does not recognize me. I had to shut down the IP6 gateway to get into the account.

scrollaway• 5 years ago

You have a static ip4 but not a static ip6? Or does bittrex not allow whitelisting an ip6?

usr11066• 5 years ago

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.

CyberShadow• 5 years ago

You can configure your operating system to prefer IPv4 over IPv6. On glibc systems, this can be done by adding e.g. "precedence ::ffff:0:0/96 100" to /etc/gai.conf.

vkdelta• 5 years ago

What is special with this book? It is standard Cisco press book.

1_player• 5 years ago

No one is talking about it, the rest of the comments are unrelated war stories about IPv6 deployment with have nothing to do with TFA.

doingtheiroming• 5 years ago

The fact that the current version was published 2017 (so 2016 info) and IPv6 is still a moving target? I suspect that isn’t the reason to post it but it’s relevant.

Asmod4n• 5 years ago

You might also be interested in https://ipv6.he.net/certification/

znpy• 5 years ago

It seems that no one is actually debating the book itself. So I ask:

- is it good as a first book on ipv6?

- does it require Cisco hardware or is it generic enough?

justshowpost2• 5 years ago

You are asking in vain, Reddit News clientele are worrying about globalist stuff like saving our planet from climate hoax etc. While the book is typical Cisco Press style, very in-depth, CCNP+ tier complex, that's too much for redditors.

usr11066• 5 years ago

Has anybody read the book? How would you describe the writing style?

yardstick6• 5 years ago

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 often have a plethora of networks at a location, and the business/franchise owner is not tech literate, or even if they were, the equipment is managed by third party vendors and they don’t want to customise their IP network for each location. It makes for messy deployment and maintenance.

- Can’t just simply open a firewall rule on the main site router to forward say HTTPS to an internal service. Why? Not all ISPs give static IPv6 prefixes, not all PCs/servers/devices support DHCP6 for static leases, and then there’s IPv6 privacy addresses. Yes, you can statically configure (only if ISP is static too!). No, I don’t want to open the port to all devices on the LAN and no I can’t rely on each device to be running their own firewall (let alone a properly configured one!).

- WAN failover / multiple ISPs is hard. You have a fibre primary feed, and a secondary cellular/5G feed. Each has different IPv6 addresses. How do you ensure the right ISP is used at any given point? IPv6 shifts this decision to the client. This makes load balancing and policy based traffic routing (eg VoIP over fibre 1, FTP over fibre 2, etc). Also the cost of using a multi-homed IPv6 subnet & BGP in a SME/retail business is out of the question (plus the cellular ISP wouldn’t support it anyway).

All the above works fine out of the box with IPv4 and NAT. It’s bread and butter easy. At the cost of not having dedicated unique public IPs but these places simply don’t need them.

What IPv6 should have done to ensure a smooth migration is allowed for NAT from the very start. That would have let everyone who needed public IPs get them straight away, and those that didn’t to still migrate anyway with as little drama as possible. But it’s just not the case, NAT has been slowly added but it’s support is far from ubiquitous that IPv4 has.

jiggawatts3• 5 years ago

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 public range internally and they have 5 ISP uplinks. They don't need to renumber their internal range just to fail over to another link.

ALL of the other issues are caused by vendors selling garbage products that have IPv6 as a "checkbox" tick without real support.

The real problem is that network engineers around the world let them get away with it, because they avoid IPv6 because of this perception that it isn't mature.

The protocol is over two decades old! It's been fully supported since Windows 2000! My phone is IPv6. My fibre LAN is IPv6. It just works.

What doesn't work is this attitude where people just like you continue to pay for products that only pay lip service to the future.

I've gone on rants here before about enormous service providers like AWS and Azure providing IPv6 "support" that is an absolute garbage fire. Totally worthless. Useless beyond belief. Literally counterproductive in the case of Azure, where turning on IPv6 anywhere will break unrelated IPv4 functionality!

Nobody ever chimes in to say: "Yes, we agree, this is bad."

Nobody ever says "Microsoft should fix this!"

Nobody has a problem. So now we have situations like the one you just described, where people are still buying routers in 2021 that that can't handle the most basic IPv6 functionality.

IPv4 addresses are now USD $40 each and rising exponentially. I really do hope the COVID case number graphs taught some of you in a visceral sense what the world "exponential" means. Hint: it doesn't mean that it'll cost $60 in a decade. Try $40000, each.

My ISP uses carrier-grade NAT on IPv4, breaking sites all over the place. I had to call them to enable a dedicated IPv4 address. Their annual investor report says that they will run out within a couple of years. Get one now while you can is the message.

Do you have any idea how much code is required for two PCs to communicate directly now, with up to 4 NAT layers as a common scenario? It's a huge library you have to integrate in your code and then you need a cloud service to assist it.

This is madness, and network engineers around the world are perpetuating it.

yardstick6• 5 years ago

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 public range internally and they have 5 ISP uplinks. They don't need to renumber their internal range just to fail over to another link.

Neither does anyone using IPv4.

Does your customer use BGP for that public IPv6 range? Do they have cellular links? Can they load balance some traffic over two/three links? Can they direct certain protocols over different carriers?

hansel_der7• 5 years ago

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 at all and most importantly; expect things to occasionally fail.

rnhmjoj• 5 years ago

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, and then there’s IPv6 privacy addresses

1. you don't need a static prefix to write a firewall rule: you can simply remove the dynamic prefix with a mask and match the EUI-64 suffix. For example with ip6tables it's something like this `::e2ab:8fff:fe12:3b6b/-64`.

2. All IPv6 devices do support SLAAC with a stable address mechanism, either EUI-64 or stable privacy address and you can use that in the firewall rule.

3. IPv6 privacy extensions, when enabled, don't preclude listening and accepting connection on the EUI-64 address. So, an inbound traffic firewall rule will just use the stable address: you shouldn't listen on a privacy address, they are for outbound connections.

Each has different IPv6 addresses. How do you ensure the right ISP is used at any given point? IPv6 shifts this decision to the client.

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

IPv6 shifts this decision to the client. This makes load balancing and policy based traffic routing

I can't comment on this because I never tried it, either on IPv4 or IPv6. On top of my head, I'd say it would be possible by updating the routes priorities with an RA, if you don't want or can't do a NAT66 with a ULA prefix.

At the cost of not having dedicated unique public IPs but these places simply don’t need them.

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.

yardstick6• 5 years ago

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...

ivlad2• 5 years ago

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 2-3-4 layers of NAT, this is just crazy.

Can’t just simply open a firewall rule on the main site router to forward say HTTPS to an internal service. Why? Not all ISPs give static IPv6 prefixes, not all PCs/servers/devices support DHCP6 for static leases, and then there’s IPv6 privacy addresses.

ISPs not providing static prefixes is a particular ISP problem, not an IPv6 problem. If your ISP cannot hand out static IPv4, you have a similar problem and tge workaround would be what? Dynamic DNS? Admittedly we had /32 and own ASN, but in remote offices where you don’t buy transit, you live on PA addresses (and of course they are static). From what I know, some ISPs don’t issue static prefixes to residential customers, but if you want to serve services from your prefix, use a stable prefix and a decent ISP.

Privacy addresses are intended for client-initiated traffic, so no matter how many privacy addresses your server has, the stable one is still there.

WAN failover / multiple ISPs is hard. You have a fibre primary feed, and a secondary cellular/5G feed. Each has different IPv6 addresses. How do you ensure the right ISP is used at any given point?

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.

ksidn• 5 years ago

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.

Is it? I'm behind two layers of nat and everything works fine.

yardstick6• 5 years ago

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).

elktea• 5 years ago

router that do BGP are cheap, especially if you're only taking a default route which is all you're going to need for using multiple ISPs for redundancy.

yardstick6• 5 years ago

It’s not the router that is the problem with BGP, it’s the ISPs. Will your cheap as chips cellular carrier support BGP? Will your local cable provider? Probably not.

gorgoiler• 5 years ago

I highly recommend the Cisco material.

I learned IPv4 from blog posts written by people who read other blog posts and HOWTOs. It worked because I came along when everyone had (and needed) the experience.

IPv6 is harder because it’s the upgrade path, not a necessity. For that, I needed good professional source material. As do you: treat yourself!

justshowpost2• 5 years ago

Should be (2017)

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

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