Recommended IPv6 setting with Comcast IPv4

Discussion in 'Asuswrt-Merlin' started by neil0311, Jan 5, 2013.

  1. neil0311

    neil0311 Regular Contributor

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    My Comcast connection only supports IPv4 at this time, at least as indicated by the cable modem which list the "Modem IP Mode" and "DOCSIS MIMO" as "IPv4 Only."

    Given that, what is the best setting for IPv6 on the RT-N66U? I was going to disable, but wasn't sure if 6to4 would be a better choice. Any suggestions, and I'll admit that IPv6 isn't something I understand well. What issues might come up as a result of disabling IPv6?
     
  2. RMerlin

    RMerlin Part of the Furniture

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    At this point, IPv6 is mostly an experimental thing (Internet-wise). Keeping it disabled will have no impact at all. You shouldn't enable an IPv6 tunnel unless you were prepared to subscribe to a tunnelling service (such as Hurricane Electric's TunnelBroker) and configure it. And in most case it will result in a drop of performance when accessing some IPv6 enabled sites such as Youtube, depending on how close network-wise you are to HE's tunnel endpoint.
     
  3. m00ster

    m00ster Occasional Visitor

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    Hello,

    The setting you are describing on your modem where it says ipv4 only is only for the management interface of the modem not the customer interface. You may have full ipv6 service.

    the correct setting for comcast ipv6 is the DHCP with PD option. Try setting that and saving/rebooting your router. I have comcast and ipv6 works perfoect for me with the AC66 router.

    -Jon
     
  4. neil0311

    neil0311 Regular Contributor

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    Thanks Jon. How can I test to see if IPv6 is enabled on my connection?
     
  5. m00ster

    m00ster Occasional Visitor

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    open a cmd prompt and type ipconfig /all and see if you see something like:

    IPv6 Address. . . . . . . . . . . : 2601:c:9e:6:886:4b69:d0db:e8ff(Preferred)

    you can also try:

    ping www.kame.net

    if you get a response back from a ipv6 address, you have ipv6.

    -Jon
     
  6. neil0311

    neil0311 Regular Contributor

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    Assuming that I need to enable DNS and router advertisement as well as setting connection type to "Native with DHCP-PD"
     
  7. KevTech

    KevTech Senior Member

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    Wait a second...not all Comcast customers have access to native IPv6 yet.

    All of the Arris DOCSIS 3.0 C4 CMTS now have IPv6 but many Cisco CMTS still do not.

    It all depends on what CMTS serves your area.

    I am in a Cisco area so I have router set to 6to4.

    Here is a map of IPv6 enabled areas for Comcast:http://goo.gl/maps/sL3Z

    If you are not in one of these areas then you most likely do not yet have native IPv6 available to you through Comcast.
     
    Last edited: Jan 5, 2013
  8. neil0311

    neil0311 Regular Contributor

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    I'm outside Atlanta, so I'm assuming my Comcast connection doesn't have IPv6 enabled. If it's not, which I think is the case, then do you recommend setting the router to 6to4 or to disabled? If 6to4, any changes to the defaults needed? Leave router advertisements on and the Anycast relay IP to 192.88.99.1?

    I did ping www.kame.net and only get a reply from an IPv4 address.
     
  9. KevTech

    KevTech Senior Member

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    See my previous post as I added a map.
     
  10. m00ster

    m00ster Occasional Visitor

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    Hello,

    It is possible you don't have ipv6 service if you are using Cisco equipment in your plant. The worse thing that will happen is you do not get a ipv6 address or connectivity, pretty much the same thing you had before you enabled ipv6 support. You can get a tunnel from a broker if you really want it regardless.

    -Jon
     
  11. saintdev

    saintdev Regular Contributor

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    It is also possible your CMTS has IPv6 enabled, but your modem doesn't support it. Comcast's DOCSIS Device Information page has a list of which modems support IPv6. If you lease your modem and it is one that doesn't support IPv6, you can try taking it to your service center and see if they will exchange it for one that supports IPv6. The counter person probably won't know what you're talking about, so take the list with you. I did this, the counter person was happy to let me choose which modem I wanted of the models they had available.
     
  12. bigcid10

    bigcid10 Regular Contributor

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    my cisco 3000 modem was not v6 ready so I switched to a ubee that is
    On the Comcast website their is a support forum that has a v6 rep who monitors
    the site ,check it out they fixed my issues
     
  13. RogerSC

    RogerSC Very Senior Member

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    Works well for me also, but Comcast has to have it going where the original poster is, and as mentioned above, their cable modem needs to support IPv6 as well. Although I sometimes have to clear the nvram and reload my settings, it will usually come up after a reboot (or two).
     
  14. neil0311

    neil0311 Regular Contributor

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    My cable modem is a Moto SB6120 which supports IPv6, but I don't believe Comcast has lit it up yet. I've disabled it in the RT-N66U.
     
  15. RogerSC

    RogerSC Very Senior Member

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    You can talk to Comcast tech support about the timing of IPv6 implementation in your area. I did that, and found that it was up, even though I didn't know it since the router firmware versions that I had used didn't work right. I had to wait for a router firmware release that supported DHCP-PD, and then it started working just fine for me.
     
  16. KevTech

    KevTech Senior Member

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  17. RogerSC

    RogerSC Very Senior Member

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