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RT-AX88U IPv6 Default GW Missing

Discussion in 'Asuswrt-Merlin' started by salami, May 24, 2019.

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  1. salami

    salami New Around Here

    Joined:
    May 24, 2019
    Messages:
    2
    Hi all

    I have used different models running Asuswrt-Merlin (legacy) for several years with the same ISP (Init7) and IPv6 has always worked very well.

    Since upgrading to an RT-AX88U (the first time running a NG FW), the router no longer detects the default GW:

    upload_2019-5-24_14-37-13.png

    This obviously breaks all IPv6 connectivity. Manually setting the GW using the following command seems to "fix" the issue:
    Code:
    ip -6 route add default via fe80::523d:e5ff:fea8:b87f dev eth0
    Thanks to the wonders of Asuswrt-Merlin, adding this to the wan-start script looks like a permanent fix. At least until my ISP changes its router...

    The official FW from Asus shows the exact same issue.

    Can anyone here help me analyze the root cause? Or how would you recommend reporting this to Asus?

    Thanks!
     
  2. EmeraldDeer

    EmeraldDeer Very Senior Member

    Joined:
    Dec 22, 2017
    Messages:
    503
    Location:
    Massachusetts
    I don't know the root cause or about reporting to Asus.
    When I raised this issue in the forums, @themiron recommended an alternative work around where you enable IPv6 router advertisement. This works and avoids the specifics of adding a route.
    Code:
    # cat /jffs/scripts/wan-start
    #!/bin/sh
    CONFIG=$1
    source /usr/sbin/helper.sh
    #
    #echo "1" > /proc/sys/net/ipv6/conf/all/accept_ra
    #echo "1" > /proc/sys/net/ipv6/conf/all/forwarding
    echo "1" > /proc/sys/net/ipv6/conf/eth0/accept_ra
    echo "0" > /proc/sys/net/ipv6/conf/eth0/forwarding
    #
    
     
    L&LD and Swistheater like this.
  3. salami

    salami New Around Here

    Joined:
    May 24, 2019
    Messages:
    2
    Thanks a lot for sharing that! My first tests are positive, looks like this fixes my case as well. And it seems to be a lot more reliable than having the GW address in the script.
     
    Swistheater likes this.
  4. Swistheater

    Swistheater Very Senior Member

    Joined:
    Jul 8, 2017
    Messages:
    1,204
    Location:
    Florida
    it is better because that GW address could be dynamically changing and no telling how often your isp changes it... granted it probably rarely happens because ISP's can be cheap.
     
  5. universe83

    universe83 Occasional Visitor

    Joined:
    Dec 7, 2018
    Messages:
    30
  6. Swistheater

    Swistheater Very Senior Member

    Joined:
    Jul 8, 2017
    Messages:
    1,204
    Location:
    Florida

    I believe asus might have released a firmware fix already I am not sure...., I think it is still in beta and you would have to wait for release of it and GPL of it to be compiled against merlins firmware... be patient.
    You have to forgive asus devs and the junior techs involved all this could be avoided if they fix things while it is in beta... Nevermind that and how occasionally spanish slips its way onto the english gui.