Enable NAT66 on OpenWrt

OpenWrt supports native IPv6 masquerading on the firewall zone.

1. Enable IPv6 Masquerading on WAN:

   uci set firewall.@zone[1].masq6="1"
   uci commit firewall
   service firewall restart

   (Note: Ensure @zone[1] corresponds to your WAN zone, or check your firewall zone index via uci show firewall).

2. Announce the ULA Default Route:
   For internal devices (using Unique Local Addresses, or ULA, starting with fd...) to know where to send traffic, announce the default route via Router Advertisements (RA):

   uci set dhcp.lan.ra_default="1"
   uci commit dhcp
   service odhcpd restart

   Use code with caution.

    

3. Disable IPv6 Source Filtering:
   Allow upstream interfaces to process translated source addresses:

   uci set network.wan6.sourcefilter="0"
   uci commit network
   service network restart

   Use code with caution.