I am trying to follow my ISP instructions on how to setup IPv6 with Luci interface but could not find "Enable IPv6 negotiation on the PPP link" in Network/Interfaces/WAN Advanced settings. The following are the full instructions, everything are there except the one I mentioned.
In Network / Interfaces / WAN
Go to Advanced Settings
Check "Use builtin IPv6-management" and "Enable IPv6 negotiation on the PPP link"
Then save and apply.
If there is no interface called wan6 in Network / Interfaces you need to create a wan6 interface with these settings:
Protocol: DHCPv6 client
Request IPv6-address: try
Request IPv6-prefix of length: automatic.
Advanced settings:
Check: Bring up on boot, Use builtin IPv6-management, Use default gateway, Use DNS servers advertised by peer.
Physical Settings:
Custom Interface: @wan
Firewall Settings:
WAN
Then save and apply.
After go to Network / Interfaces / LAN
Set "IPv6 assignment length" to 64
At the bottom DHCP Server section:
IPv6 Settings
Router Advertisement-Service: server mode
DHCPv6-Service: server mode
NDP-Proxy: disabled
DHCPv6-Mode: statless + stateful
Save and apply.
Reboot and you should have IPv6 on the WAN interface and a /64 subnet on your LAN. LAN devices should be getting IPv6 addresses also.