There is debate as to whether you are or are not a Full Node if you are not receiving incoming traffic. In my view, you are not an optimized Full Node if your incoming traffic is zero. But what I don't understand is this: What is the degree of support of consensus mechanism given Full Node with versus without incoming traffic? Anyone?
Whether you accept incoming connection or not, your node always verify all block and transaction.
Here are some steps to configure incoming traffic.
1. Look on the label of your router/modem for the IP address of the device. Enter that into the address bar of your browser. The device's menu will load.
2. Go to Advanced and Port Forwarding. If your menu lacks Advanced/Port Forwarding, you must upgrade your modem. I had to do that with my telecom Altice in the Dominican Republic.
3. Enter 8333 in all fields and save. Reboot modem and computer.
4. Go to: bitnodes.io The site will recognize your IP address. Scroll down a bit and click search to see if you are recognized. I am a noob running the only BTC Full Node in the Dominican Rpublic
and Haiti for several years.
As reminder, it doesn't work for those who use ISP which use CGNAT.