My Linux and OpenWRT both have dual ipv4 & ipv6 address assigned by my ISP via DHCP.
The tunnel itself is working fine when the Wireguard tunnel is formed over IPv4. I can see handshake packets exchanging, and ping remote wg interface IP works.
Now, I when switch the tunnel over to IPv6, by side effect after I added the IPv6 AAAA records to my DDNS provider.
I can see both Linux and OpenWRT are trying to form the tunnel over IPv6 address. But there is no handshake packets exchanged. (Send is increasing, Received is always zero at both ends.)
What I need to do to allow the tunnel forming over IPv6 addresses?
It's a good idea to use tcpdump to verify that the packets are sent out via the correct interface and check if you receive any incoming packets. Also check the host route inserted by openwrt to the peer endpoint. It might be wrong under some conditions.