Cannot Use DDNS Behind NAT?

[Boris_yo]

Hello,

My ISP routes my bandwidth through NAT and also assigned me dynamic public IP address. I read on Reddit mixed answers. Some say I can use DDNS service behind NAT, others say I can't.

I activated DDNS in my ISP's cable modem and successfully linked to NO IP DDNS host address provider. It does not however auto-update my public IP. I checked DDNS status in cable modems options and the message I get is as follows: "Current IP matches last update, so update is not required."

Not sure why this doesn't work. Is my cable modem supposed to send updates to NO IP every time my ISP updates my public IP?

Thanks