Hello,
Could you please clarify if you have configured you WAN interface as LAN?
Also, does RUT955 get internet access from a SIM card?
I would suggest restoring the device configurations to defaults, and do the following:
Set LAN ports to be on the same network as the cameras, i.e. 192.168.1.0/24. For example, 192.168.1.254. Then, configure WAN port with an IP address of 172.16.1.1.
After configuring the LAN and WAN settings, you can proceed to set up NETMAP rules. You can find an example for simiar case in this forum post here. Be sure to adjust the IP addresses to match your specific setup. These rules will handle incoming (prerouting) packets by directing them to the cameras in LAN and outgoing (postrouting) packets by rewriting their source to the 172.16.1.0/24 network.
Kind Regards,