PS4 NAT type 3 on Asianet broadband

Messages
1
Location
Kottarakara
ISP
Asianet Fiber
I am using Asianet Fiber broadband with optilink router. I am trying to obtain open NAT on my PS4. I assigned a static ip to my PS4 using DHCP server and turned DMZ on in that ip. Did not help. Tried UPNP and port forwarding, individually and together. But still nat type 3 on PS4. Can someone help me?