@Abbienormal 

I understand that you want to open port 8883 on your Deco Mesh system.

To do this, you will need to set up Port Forwarding for port 8883 through the Deco app. Here’s how you can do it:

1. Open the Deco app on your mobile device.
2. Go to MORE > Advanced > NAT Forwarding > Port Forwarding.
3. Tap the "+" icon to add a new port forwarding rule.
4. Select the device on your network that you want to forward port 8883 to.
5. Enter 8883 as both the internal and external port (unless your application requires a different internal port).
6. Choose the correct protocol (TCP, UDP, or both) as required by your application.
7. Save your settings.

Notes:
• Port Forwarding is only available when your Deco is in Router mode. If your Deco is set to Access Point mode, this feature will not be available.
• When you create a port forwarding rule, the Deco app will automatically reserve the IP address for the selected device to ensure the port forwarding continues to work reliably.

For more detailed instructions, you can refer to this FAQ: https://www.tp-link.com/support/faq/1797/