The virtual host port uses two ports to communicate with the IP camera. Each channel on the NVR will have two unique ports.
The virtual host port will start at 591XX for HTTP, 581XX for DATA. XX= ChID.
You can port forward these ports to gain remote access to an IP camera. This is particularly useful for cameras where settings tweaks must be done off site.
When you click the settings icon for the camera, it will redirect you an add the virtual host's port # associated with the channel.
For example,
This means channel 1 uses port # 59101 for the HTTP port. You must also forward 58101 for data.
Channel 1: 59101 for HTTP. 58101 for DATA.
Channel 2: 59102 for HTTP. 58102 for DATA.
Channel 3: 59103 for HTTP. 58103 for DATA.
and so on.
After port forwarding the two ports and confirming that the ports are open you can access it through the WAN IP or DDNS address.