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Forum Discussion

TheCube's avatar
TheCube
Aspirant
Mar 29, 2023

[BUG] IPv6: 6rd support breaks after an IPv4 change

Hello,   For context, I'm using CenturyLink fiber, which offers IPv6 through 6rd.   The problem: with 6rd, IPv6 autoconfig works only on the initial connection. It does not happen on subs...
FURRYe38's avatar
FURRYe38
Guru - Experienced User
Mar 29, 2023

Please make contact with NG support to let them know this:

https://my.netgear.com/support/contact.aspx
https://www.netgear.com/about/contact-us/

TheCube wrote:
Hello,
 
For context, I'm using CenturyLink fiber, which offers IPv6 through 6rd.
 
The problem: with 6rd, IPv6 autoconfig works only on the initial connection. It does not happen on subsequent IPv4 changes.
 
Reminder: RFC 5969 (for 6rd) states:
The 6rd delegated prefix for use at a customer site is created by combining the 6rd prefix and all or part of the CE IPv4 address. From these elements, the 6rd delegated prefix is automatically created by the CE for the customer site when IPv4 service is obtained. This 6rd delegated prefix is used in the same manner as a prefix obtained via DHCPv6 prefix delegation [RFC3633].
When configuring the Orbi router with 6rd, it should use the configured IPv6 prefix with the IPv4 from the ISP to auto-configure an IPv6, which can then be used for router advertisements on the LAN side.
 
However, I have a dynamic IPv4 which changes about once a week. Every time I get a new IPv4, I lose IPv6 connectivity because the 6rd-derived IPv6 is not reconfigured after the IPv4 change.
 
This seems like a bug in Orbi's handling of 6rd. Only way for me to get IPv6 connectivity back is to reboot the Orbi so it does auto-config again.
 
Posting this in remote hopes that someone at Netgear is looking at this. Please fix in the next firmware - thanks 🙂
 
Router model: RBR750
Firmware version: V4.6.14.3_2.3.12

 

    • FURRYe38's avatar
      FURRYe38
      Guru - Experienced User
      Mar 29, 2023

      I'll pass this on to NG.

      KevinLiT 

      • TheCube's avatar
        TheCube
        Aspirant
        Mar 29, 2023
        FURRYe38 wrote:

        I'll pass this on to NG.

        KevinLiT 


        Excellent, thank you so much!

         

        In case that helps anyone, I wrote this ugly bash script (works on Linux) to detect when the Orbi needs to be rebooted. Should work with CenturyLink, but may not work elsewhere as the length of the 6rd prefix may vary depending on the ISP (/24 on CenturyLink). Just need to change/shift the sed regexp to adapt.

         

        #!/bin/bash

ip4=$(curl -4 -s ipinfo.io | jq -er .ip)

ip6=$(sipcalc $(ip route get ::1234 | sed 's/.*src \([^ ]*\).*/\1/') | grep -F Expanded | cut -d '-' -f 2 | tr -d ' ')
ip6to4=$(echo $ip6 | sed 's/....:..\(..\):\(..\)\(..\):\(..\)..:....:....:....:..../printf "$((0x\1)).$((0x\2)).$((0x\3)).$((0x\4))"/' | bash -s)

echo "IPv4: $ip4"
echo "IPv4 from 6rd: $ip6to4"

if [[ "$ip4" != "$ip6to4" ]]; then
    echo "Reboot the Orbi" >&2
    exit 1
fi