Model :

Hardware Version : Not Clear

Firmware Version :

ISP :

I just bought a TP-Link Archer C2 AC750 for it's USB port, IPv6 Compliance and FTP Server.
My network is as follows:
- 192.168.1.254 my ISP's (Fastweb) fiber optic router with IPv6 support; only settings available: WiFi switch/security and Port Mapping... its WAN IP address is private and a public IP has a daily cost.
- 192.168.0.1 TP-Link Archer C2
- Ethernet and WiFi devices.

I plugged an Hard Disk and configured FTP to allow connection from the WAN port. within both subnet the Archer C2 is accessible using the respective IPv4 address. Using the IPv6 address it is not accessible from the "wan" subnet (nor the actual WAN):
It looks like the FTP daemon is being bind to the IPv4 address only... (huge problem)
The problem branches here as I'm not able to test IPv6 binding from within the Archer C2 LAN as apparently it doesn't assign an IPv6 to my devices (funny as my old 2009 belkin allowed them to connect, be pinged and offer FTP connectivity to the world in the very same fisical configuration).

I tried to set it as Dynamic IPv6/SLAAC on WAN and RADVD/Delegated on LAN but no IPv6 Address is assigned to any device (the router has it assigned and is pingable from the "wan" subnet and from the online ping services).
Setting it to DHCPv6 on LAN gives no results while leaving it to RADVD/Static Prefix assigns the same IPv6 Address that the devices had on the "wan" subnet having them unreachable by the world outside the LAN (the main router is not routing anything to the Archer).
I guess the problem is somewhere among 6rd (tunneling in general) and something else

Help.
Thanks in advance