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Thread: IPv6 readiness

  1. #1
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    Question IPv6 readiness

    Hello.

    I've heard about the exhaustion of IPv4 addresses, and I roughly know what IPv6 is.

    Does anyone know how to check whether our hardware (network adapters, routers, etc.), and software (operating systems, browsers, etc.) are ready for the transition?

    Thanks in advance.
    Last edited by JFekete9076; February 10th, 2011 at 04:44 PM.

  2. #2
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    Re: IPv6 readiness

    Quote Originally Posted by JFekete9076 View Post
    Hello.

    I've heard about the exhaustion of IPv4 addresses, and I roughly know what IPv6 is.

    Does anyone know how to check whether our hardware (network adapters, routers, etc.), and software (operating systems, browsers, etc.) are ready for the transition?

    Thanks in advance.
    First, make sure that your ISP provides you with v6 connectivity, then go to http://ipv6-test.com and do the connection test.

    If it shows your v6 address and related infos, then you're onboard.

    You may also have to enable it on your router if it doesn't work.

  3. #3
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    Re: IPv6 readiness

    My whole network runs dual stack with an IPv6 tunnel from Hurricane Electric.

    Most (all?) operating systems these days have IPv6 functionality including Linux, Windows xp and newer, and Mac os X. Heck, even apple iOS4 and above is IPv6 functional even though they don't advertise the IPv6 address anywhere in the settings.

    most low level hardware like switches and nics and such will also handle IPv6 with no issue.

    Routers are the problem, most don't. I know apple Airport Extremes do, as well as anything running DD-WRT or tomato. Personally I just use an old computer running linux to handle my IPv6 routing.

  4. #4
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    Post Re: IPv6 readiness

    Which routers are IPv6-ready?
    I am using TP-Link WR340GD, which was bought in 2010.

  5. #5
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    Re: IPv6 readiness

    The transition from v4 to v6 is a lot like the transition from analog to digital TV; new gear all around to mostly get the same content. The odds are high that your existing broadband modem and wifi router don't actually support v6 properly and will have to be replaced in 2012 or 2013. Waiting is a good consumer move, as quantity, quality, and prices of v6-capable gear will be improving rapidly in the next 6-18 months.

    Finding out if your current gear supports v6 takes some doing; look up the exact model on-line and see if it's mentioned as a supported feature. If not, be pessimistic. If you have access to administrative interfaces, see if they have any v6 features visible; if not, be pessimistic. It's a fair amount of work to actually test for v6 if your ISP doesn't support it already, so that's probably not worth the effort. If you can reflash a device with 3rd party firmware, and it has enough memory of the various types (flash, ram), a lot of the linux router firmwares such as dd-wrt have v6 support.

    On the OS front I recommend being on recent software, so serious v6 folks want windows 7, this summer's Mac OS-X 10.7 "lion", Redhat 6, etc. v6 support in recent versions of Ubuntu is pretty good. All modern browsers support "dual-stack" operation of v4 or v6 in parallel, so you are OK there, too.

    ISPs and hosting providers need to support v6 ASAP, as their business customers will be demanding it. Businesses may or may not need to rush; if they have asian customers, asian supply chains, mobile customers, or government contracts they need to hurry on v6 support, at least for their outward facing services. Note that in the US smartphones are outselling computers, and 4G smartphone rollouts are all dual-stack-lite, with native v6 only; their v4 support is legacy v4 over v6 tunnels to carrier NAT44 translators. Which is why the likes of google, youtube, facebook, netflix and cnn are already dual-stacked. Enthusiasts don't have to wait for their ISP's to offer native or near-native (6rd) v6; they can set up IPv6 over v4 tunnels, e.g. with hurricane electric's "tunnelbroker.net", sixxs, or gogo6. The one gotcha there is that your wifi router has to pass protocol 41 (IP over IP) too, not just protocols 1,6,17 (ICMP, TCP, UDP). I recommend point to point tunnels rather than 6to4 (not available to most home users behind NAT devices) or Teredo (only for masochists).

    The likely timetable is: RIR's run out of most v4 in 2011, ISP's run out in 2012, the year of the IPocalypse is 2013 - when new v4 is hard to get but v6 availability is still problematic. Widespread world-wide availability of v6 is probably 2015. 99% v6 traffic is probably 2017. Tier-1 ISP's turning off v4 routing on the global internet backbone is probably 2020. The last v4 device lingers till, say, 2036.

  6. #6
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    Smile Re: IPv6 readiness

    Thank you for the answer.

  7. #7
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    Re: IPv6 readiness

    Quote Originally Posted by lemming465 View Post
    I recommend point to point tunnels rather than 6to4 (not available to most home users behind NAT devices) or Teredo (only for masochists).
    And is Miredo the Linux equivalent of Teredo?
    The Teredo IPv6 tunneling protocol encapsulates IPv6 packets into UDP/IPv4
    datagrams, to allow hosts behind NAT devices to access the IPv6 Internet.

    Miredo is a Teredo client (as per RFC 4380): it can provide IPv6
    connectivity to a dual-stack IPv6/IPv4 host even if it is located behind a
    NAT. It can also operate as a Teredo relay which forwards IPv6 packets
    between the IPv6 Internet and remote Teredo clients.
    I've just stated looking into this and am not sure how this works and was wondering about your thoughts.

  8. #8
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    Re: IPv6 readiness

    One caveat with a dual-stack I have encountered. If you set up IPv6 on your LAN, but do not have IPv6 connectivity, yet, you will get long waits during DNS lookup. This is because Ubuntu enabled IPv6 in the resolver, which will cause it to query for AAAA records before falling back to A records. If a site has no AAAA records, you wait until your resolver asks for A records. This can be quick if the site's DNS answers negatively for the AAAA records quickly. But any slowdown causes much longer waits because the resolver tries AAAA 2 or 3 times before trying A records. If the site does not answer AAAA (some cases of this), then the delay can be significant (up to 30 seconds or so). If the site gives a positive answer for AAAA records, then things go from bad to worse if you can't reach their IPv6 addressed host. The resolver would get the IPv6 address, and the application will try to connect. Since the resolver only asks for AAAA records, and gets them, that is all that the application gets. It would have to ask the resolver specifically for IPv4 addresses as a fallback. How the application handles this can vary. Some may do very bad.
    Mask wearer, Social distancer, System Administrator, Programmer, Linux advocate, Command Line user, Ham radio operator (KA9WGN/8, tech), Photographer (hobby), occasional tweetXer

  9. #9
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    Re: IPv6 readiness

    Yes, "miredo" is the ubuntu (and Fedora) client for the Teredo protocol; I should have mentioned that. You operate it by (1) sudo aptitude install miredo (2) check file /etc/default/miredo for START_MIREDO=true (3) sudo /etc/init.d/miredo start. Points (2) and (3) are probably automatic on the install.

    If you don't want Miredo resuming every time you reboot, you need to edit it to say START_MIREDO=false instead. And to shut down tunneled IPv6, sudo /etc/init.d/miredo stop.

    The Teredo protocol assumes that you are behind a NAT44 translator (firewall / router) which doesn't pass protocol 41, but will let UDP responses in if you have previously leaked UDP packets out. Your Teredo client contacts a teredo server on well known port UDP 3544 and configures a special IPv6 address with the 2001:0::/32 teredo prefix, the v4 bits of your server, the v4 bits of your outside public IPv4 address upstream, your UDP origination port, and some random bits to reduce spoofing risks. When you want to talk to a v6 peer on the v6 internet, your client contacts the teredo server, which locates a teredo relay for you. Your actual v6 traffic goes back and forth via the relay, encapsulated many layers of headers: IPv4 header, UDP header, Teredo header, IPv6 packet. Different IPv6 peers may need different relays, so if you visit some advertising and content-distribution heavy web site which has 200 sundry servers contributing to the overall page, you could have 200 relays involved. In case of long-lived TCP connections, to keep the UDP holes open through your NAT44 device, you send keep-alive UDP packets to your server and to all recently used relays every thirty seconds.

    The good news: practically anyone can use Teredo to participate in the v6 internet, even when their ISP doesn't support native v6 and their modem and router gear doesn't support v6 either.
    The bad news: expect about a 15% failure rate reaching sites, the overhead is immense so throughput will suck, the latency is completely appalling, so time to load a complex page might be minutes, not seconds. As an R&D ploy to gain experience with v6 and reach one or two simple v6-only sites, do try it. Do not delude yourself that it is fit for routine use; you would hate that.

    On the bright side, having Teredo up probably won't cause the dual-DNS slowdown Skaperen describes, since /etc/gai.conf prioritizes native v4 ahead of tunneled Teredo. There is a debate in the v6 community at present suggesting that the cutover from legacy v4 to our shiny new v6 might go more smoothly if web clients do DNS v6 (AAAA) and v4 (A) queries in parallel rather then serially, try to open both versions of a site, and only continue with whichever responds first. Current web browsers and DNS resolver libraries don't do this, and the effects on internet congestion and server load would have to be dealt with, so who knows?

  10. #10
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    Re: IPv6 readiness

    Interesting. Thank you very much for your thoughts.

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