NAT, Tethering and hotspot

[Amir Saleh Alavi]

Hello everyone

I used an iPhone to make a personal hotspot, to connect my PC to internet via WiFi, but when I looked up my public IP using both iPhone and the PC, I received different results. I thought it supposed to act like all other routers with NAT enabled. Interestingly, when I try to get the PC's local IP, I get an IP in 172.20.a.b range.
So here is my question: why am I getting different public IPs? Like when you access internet using one cable connection and all devices connected to the router must use the same public IP.

Thanks all