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Issues with ipv6 and non-bridge modem.

Discussion in 'Asuswrt-Merlin' started by akb, Apr 8, 2020.

  1. akb

    akb Regular Contributor

    Joined:
    Sep 25, 2016
    Messages:
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    Xb6 modem comast
    ac88u merlin latest

    So there is an ongoing problem with the xb6 bridge mode from Comcast which limits the download to 600 when we pay for 1000.

    I have no ipv6 issues when I use bridge mode with the xb6, but I am reverting to being in a double nat until the bridge cap issue is resolved.

    So I got my router in a DMZ in the xb6 and ipv4 works with speeds up to 1000 like intended, but I can not for the love of god figure out how to set up ipv6.

    So setting native with everything auto, I do not have ipv6 connectivity.
    setting native with dhcp-pd off and manually putting info had the same result.
    I went even as far as setting up static IP and had the same result.

    The only time ipv6 works in this setup is when I put passthrough, which by design is not great, and even worse the download is cut to 400 in this mode which is ridiculous.

    Can someone please guide me in ipv6 which I am clueless in. thank you.
     
  2. akb

    akb Regular Contributor

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    Also out of curisoty why would ipv6 passthrough cut my download speed?
     
  3. akb

    akb Regular Contributor

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    ping6 from router to google.com works and ping6 to local plan clients works.

    local plan clients ping6 to router IPv6 works, but ping6 to google.com does not work.

    What could I be missing??
     
    Last edited: Apr 8, 2020
  4. heysoundude

    heysoundude Very Senior Member

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  5. akb

    akb Regular Contributor

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    OK maybe clueless was the wrong word. what I mean to say is clueless on how Asus handles the ipv6.

    So from troubleshooting, I can from the ac88u ping6 and traceroute6 to public internet and to local lan clients, but my local LAN clients can only ping each other but never public internet.

    the route table looks correct, but for whatever reason its not jumping from client to xb6 modem.

    Cry emoji
     
  6. john9527

    john9527 Part of the Furniture

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    If Windows, check it's firewall. For the longest time the default rules blocked IPv6 pings.
     
  7. akb

    akb Regular Contributor

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    Thanks for the advice but these are various operating systems and pings work within the local lan and to the router. The issue is outbound from lan clients to public internet. The router uses the same delegated prefix ipv6 and can reach public ipv6, and the lan clients use the same delegated prefix so I am just imagining its just the way the Asus router is setting the route correctly between wan/lan of the router.
     
  8. intr0

    intr0 Occasional Visitor

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    Try either disabling IPv6 completely on your router or using the 6rd option. It's a fairly old standard but it does function in combo with a Comcast modem using a double NAT setup.
     
  9. Smokey613

    Smokey613 Senior Member

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    Location:
    Redneck Riviera, USA
    I ran into issues trying to make IPv6 work on my RT-AC86U with the ISP cable modem. It worked fine in Native mode with the cable modem in bridge mode but, my ISP eventually blocked my router from working with their modem in bridge mode so I had to revert back to double nat. Not really an issue as even in bridge mode they use a CG-NAT so I never got an internet IP even in bridge mode. But, in my current double nat configuration, no IPv6 configuration seems to work correctly so I have abandoned IPv6. I have a static IP set on my router wan port and it is placed in a DMZ on the cable modem. This setup seems to work well enough.
     
  10. intr0

    intr0 Occasional Visitor

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    DMZ = Security Hole. I'd rather have performance issues.
     
  11. Dabombber

    Dabombber Regular Contributor

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    Have you tried setting the modem as the DHCP server, and disabling it on the router?
     
  12. Smokey613

    Smokey613 Senior Member

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    Uh, no it’s not. No difference than my router having an assigned internet IP on the wan interface. My router is still providing all the security for my network. The ISP modem is just passing all traffic to my router as if the ISP router was not in the picture. Also, I am not having any performance issues with IPv6 disabled.
     
  13. intr0

    intr0 Occasional Visitor

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    The performance issue I referred to was in relation to the OP's issue.
    The DMZ = Security Hole was a general statement for anyone who may come across this thread not knowing how to use it as you are. Apologies for the misunderstanding.
     
    Smokey613 likes this.