IPv6 does not work on QNAP

[wingcomm]

Tailscale IPv6 does not work on QNAP, will this be fixed or is it a QTS/platform limitation?

[tebriel]

Same issue, recording some of my research.

sysctl reports that ipv6 is disabled:

$ sysctl -a | grep net.ipv6.conf.tailscale0.disable_ipv6
net.ipv6.conf.tailscale0.disable_ipv6 = 1

Enabling it with:

$ sudo sysctl -w net.ipv6.conf.tailscale0.disable_ipv6=0
net.ipv6.conf.tailscale0.disable_ipv6 = 0

adds the link-local IPv6 address (fe80) to my interface but not the tailscale IPv6 Address (from within fd7a:115c:a1e0::/48)

34: tailscale0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1280 qdisc pfifo_fast state UNKNOWN group default qlen 500
    link/none
    inet 100.64.119.9/32 scope global tailscale0
       valid_lft forever preferred_lft forever
    inet6 fe80::788a:164c:c819:d899/64 scope link flags 800
       valid_lft forever preferred_lft forever

Restarting the tailscale qnap service re-sets net.ipv6.conf.tailscale0.disable_ipv6 back to 1 so that isn't a valid way to refresh the IP address.

[oxtoacart]

When Tailscale starts, it checks whether or not ipv6 is generally enabled before enabling ipv6 for Tailscale. If you enable ipv6 on all interfaces and restart Tailscale, Tailscale will assign an ipv6 address.

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=0
sudo ./share/ZFS530_DATA/.qpkg/Tailscale/Tailscale.sh restart
ifconfig
...
tailscale0 Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          inet addr:100.100.181.91  P-t-P:100.100.181.91  Mask:255.255.255.255
          inet6 addr: fd7a:115c:a1e0::901:b55c/128 Scope:Global
          inet6 addr: fe80::b622:bd16:2721:9ad5/64 Scope:Link
...