What is port forwarding?
Port Forwarding in Sophos Firewall simply reroute the incoming request from outside client to specific port of your server or DVR within a network. A public IP address are commonly used by several hosts, when you access a CCTV DVR from outside network, the request are forwarded to specific ports like http port, control port and media port. Thus, traffic will be from and to your DVR only.
First you have login to your Sophos UTM using web browser. Your default gateway address is usually the Sophos IP address also.
Assuming that you have already created new device under Network Definitions. Now create the specific service ports needed by the device.
Look for Service Definitions under Definitions & Users, then Click New Service Definition.
Fill up the Service Name, Type of Port, Destination Port and write description under Comment box, and click Save.
Now, Click NAT (Network Address Translation) Under Network Protection settings.
Click NAT on the second tab, Fill up the Service Port, the main internet Interface.
Look for the NVR device in the Destination box, and add the Service port needed, Tick Automatic firewall rule, and click Save.