Windows Resource monitor - Question about network

Question

Hello,

at the beginning my first idea was to find a software that could help me to understand a specific application/game which ports it opens and uses. The second thing was to understand if the specific application/game can open these ports when using a LTE connection (mobile connection) due to the fact that I was experiencing frequent disconnections. A tried different softwares because I didn't know the potentiality of Windows Resource monitor. After making a research on internet I see a couple of tutorials and wow...it is great. The only one thing that in my opinion is missing is the record function. To start a record while using a fullscreen application or game and after exiting the application/game to check what has been happened. Anyway, if there is a way, please let me know.

I have attached two screenshots in which I choose Anydesk as program to be monitored. One it is from my office and the other one is from my home :

With the red line I have hidden the IPs of my own locations.

So I would like to understand more about the open ports on both sides (office and home) and which ones are comunicating.

My first question : in the TCP connection tab, the local port is the open port on the local pc and the remote port is this one that is used by the remote pc, is it correct? If yes, if I use a online port scanner like https://www.whatismyip.com/port-scanner/ which port I have to find open if I check them? I tried both at home and office and while the anydesk connection is estabilished, it is showing as open only the 443. Why?

My second questions : in the office I have a firewall, so theoretically it should block most of the ports. Now looking at the made screenshots on the listening ports tab : on the office one it is empty while this one of my home it shows some records. Could you explain me what does exactly mean?

Returning to my main issue and speaking about the LTE connection (or using my office connection), using the resourse monitor is it possible to understand if the ISP/router/firewall is blocking the port forwarding on specific application? And how to check it?

Please let me know.

Thank you.

Answer 1

Hello RobertSoldano

Yes, the local port is the one on your computer and the remote is the server of the application.

Both questions can be answered with the usage of Ephemeral Ports or Dynamic Ports. These are ports assigned after the port number 1024 up to the port 65535
Reference: https://learn.microsoft.com/en-US/troubleshoot/windows-server/networking/default-dynamic-port-range-tcpip-chang

These ports are a communications endpoint (port) of a transport layer protocol of the Internet protocol suite that is used for only a short period of time for the duration of a communication session. This is why you may see some "high" ports (for example 49790 or 50001 as in your pictures) changing number from time to time, even thought the remote server is always connected with the same port outbound. The server may still communicate outbound through its 443 port, but can open different connections to other ephimeral ports in the client.

Regarding the firewall, it highly depends how it is configured. Some ports may be blocked, some ephimeral port range may be limited, and for some specific ports such as 443 that can't be blocked, some firewalls can be set as Filtered in order to inspect the packages and block specific communications.

About testing your ports while connected to LTE, I can recommend the next took from Microsoft:
PortQryUI
https://www.microsoft.com/en-us/download/details.aspx?id=24009

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