For 4G CCTV installations you may be tempted to use a SIM card directly from one of the main 4G SIM card providers which may offer cheaper data plans and more inclusive data, however in the majority of cases, whilst these SIM cards will give your 4G router a 4G Mobile Broadband Internet connection you will be unable to remotely connect to your router and that means you also can’t use DDNS / Dynamic DNS.
This is because when the router connects using your standard 4G Data SIM card, the mobile network will allocate your router with a PRIVATE IP address on their network. If you connected a PC and visited a website like www.showmyip.co.uk then you will see the PUBLIC IP address, however behind this PUBLIC IP address will be up to 250 devices, each one having a PRIVATE IP address, just like the one allocated to your router.
So – If you wanted to connect to your router you would have to call your mobile provider and ask them to disconnect the other 249 customers and to allocate that Public IP to only your connection in order to be able to remotely connect to your router. And do you know what? They ain’t going to do that!
This also means that DDNS is not going to work, because Dynamic DNS will only work if your router has a Public IP address and be be connected to from the Internet, so the fact that your router has a PRIVATE IP address means that DYNDNS will not work.
Similarly for the majority of ‘cloud services’ and remote access services offered by CCTV DVR/NVR equipment manufacturers – these tend to just be a DDNS service offered by your CCTV company so you don’t have to pay for DDNS services from DYN.ORG or NO-IP.COM. If your equipment manufacturer GUARANTEE that you connect using any SIM card, then simply get a PAYG SIM card, configure your router APN settings and get it connected and test your equipment providers promise – if it does not work then you would need to ask your cloud provider to assist you because it is likely a problem with their promised service because it relies on DDNS and if not then they will be able to get it working for you and if not it is unlikely to be a router issue.
The probable exception to this would be if your CCTV equipment connected to your cloud solution and just uploaded content for you to view when you log into your cloud service provider because the content would be stored on their server but this would not provide remote access to your router or CCTV devices in most cases.
You can read more about unlimited data Fixed IP SIM cards here.