UPnP with double NAT and dynamic ip

[lucaber]

Hi,

I enabled UPnP for my PS4 and have a small issue with the configuration.
The pfsense doesnt get the public IP because im running a double nat with my ISP router.
(No alternative router/modem available)
So my ps4 recieves my pfsense WAN IP as the external WAN address and nothing works.
But if I set the "Override WAN address" to my external IP, the ps4 nat type changed to Type2, so everything works.
The problem is that my exteranl IP is dynamic and the value in "Override WAN address" doesnt change automatically.
I have dynDNS setup, but the field only accepts IP addresses.

Is there a way to change this value to my external IP automatically?

Thanks!

-lucaber