I have moved to NBN service recently and lose my static IP address for my CCTV system. Could you please advise if I could buy a new modem comes with DDNS service from the modem vendor and replace my TPG modem ? In that case, I could keep my NBN residental plan and use my CCTV system. Please advise. Thank you.
I don't think there's any modem/router that comes with a preconfigured DDNS.
DDNS is a stand alone service.
You need to look for a DDNS service provider such as DynDNS and configure it on your device.
alternatively, you can change your plan to a Business grade NBN and get a static IP Address here's the link for details about our NBN Busisness Plan https://www.tpg.com.au/nbn-business.