How can I configure ex2 with Rasperry Pi3

Hello,

I was used to connect my WD ex2 to my router. But now I got a small Wireless without Ethernet port.

My EX2 was working fine with dyndns through my router.

As I wrote I bought a TP-LINK router http://ch.tp-link.com/products/details/cat-4692_M7350.html

Through WiFi, a Raspberry Pi 3 is connected, and I connected the WD ex2 ethernet port to the ethernet port of the Raspberry

On the WD EX2, I confgiured Dyndns (it works with my previous router) and I was hoping it work with the TP-Link router but it not the case.

I know, I can nount with NFS or Samba the WD EX2 to the Raspberry, but I would like to use my EX2 as before.

In that way, into a browser, when I enter the myex2.dyndns.org , I can get in as before.

I wonder, if some one has a experience about configuring the Raspberry, in order to have as port forwarding.

Second question. by default the EX2 has DHCP. In that way, a router can privde it a IP addres. As now, my EX2 is connected to a Raspberry and not a router, what happen, if I change the EX2 from DHCP to Static IP address and I provide an IP address in the same range that my TP-Link provide IP addresses?

NB: I can access the EX2 with the raspberry browser (ex.local)

I hope you understand my french-english :o)

many thank for your help
Cheers

PS: I also would like to use GIT application on my EX2