While we were configuring the Firewall on our Synology NAS. We found it useful to have a quick way to check if ports that we were working with were open or closed.
So built into Windows PowerShell is a command called Test Net Connection (TNC), which is a free way to check the state of our firewall. Please note that TNC does have limitations but seems to work well when checking if a single port on our NAS is open or closed.
Quick reference notes:
- From the desktop of Windows 10, select Search
- Within the search field enter Powershell
- Now from the command prompt of Powershell enter the following:
tnc <ip address of NAS> -port <the port to be tested>
- When you press enter on your keyboard the test will run.
Notes: While you can test a range of port numbers, for example ports between 150 and 200. As most of those ports will be closed, you will have to wait for the TNC command to time-out for each port. As the test for each closed port will take roughly 70 seconds. If you test a range of ports, it will take a considerable amount of time.
If you need to test the whole firewall on your NAS, or you wish to test a range of ports. It would be more time efficient to use a full network scanning application.