Problem about IPv6 support

[valkjsaaa]

I have built a docker image from master branch to get IPv6 support on my VPN.

However, it seems that I can get an IPv6 address, but it is not forwarding any package.

The result of docker logs is.

net.ipv4.ip_forward = 1
net.ipv6.conf.all.forwarding = 1
net.ipv6.conf.eth0.proxy_ndp = 1
ip6tables v1.6.0: can't initialize ip6tables table `nat': Table does not exist (do you need to insmod?)
Perhaps ip6tables or your kernel needs to be upgraded.
ip6tables v1.6.0: can't initialize ip6tables table `nat': Table does not exist (do you need to insmod?)
Perhaps ip6tables or your kernel needs to be upgraded.
(notice) ndppd (NDP Proxy Daemon) version 0.2.4
(notice) Using configuration file '/etc/ndppd.conf'
(warning) Low prefix length (64 <= 120) when using 'static' method
Starting strongSwan 5.3.5 IPsec [starter]...
removing pidfile '/var/run/charon.pid', process not running
sh: 1: modprobe: not found
no netkey IPsec stack detected
sh: 1: modprobe: not found
no KLIPS IPsec stack detected
no known IPsec stack detected, ignoring!
charon (32) started after 60 ms

I tried to modprobe a few ipv6 modules on my hosting system, but that does not seem to help. Is there anything else that I should do for IPv6 support?

Thanks