Port 80 is the default HTTP port on most DVR / NVR models. If you lose network connection to your DVR / NVR system because your Internet service provider (ISP) blocked port 80, you will need to open port 80 or change the HTTP port.
To resolve a blocked port issue:
IMPORTANT: If you are port forwarding and you change your HTTP port from 80, you will need to alter the Dynamic Domain Name System (DDNS) or external IP address link you connect with when using a web browser. For example, if your DDNS was firstname.lastname.lorexddns.net and you changed your port to 8080, your new DDNS would be firstname.lastname.lorexddns.net:8080.