Unable to specific ports on my Azure VM machine

Question

Hey there,
I'm stuck trying to build a video management system on a windows 10 VM computer using Azure.
For testing I've disabled all firewalls.
I am trying to open various ports that the video management software needs to be able to function, I've gone through all the steps in this article https://learn.microsoft.com/en-us/azure/virtual-machines/windows/nsg-quickstart-portal

I am able to open port 559 with no issues, copying that exact configuration to port 560 and 561, they stay closed, they are not listening on the computer, tested with netstat -a in command promt, and also used 3rd party port checker websites to confirm, specifically portchecker.co, it shows open on 559, and when i delete the port config for 559, portchecker shows closed, redo the config, it shows open, try the same config except changed the port to 560, no luck...I've got about 20 ports to open so this software works properly...any help would be greatly appreciated

Answer 1

Hello @Xander Traptow ,

This will be due to one or more of the below reasons:

1. There is an NSG at the subnet level as well which is blocking the port.
2. There is a firewall on the VM its self (windows firewall etc.).
3. There is nothing listening on that port.

You should check your service first. To find specified open port, use find switch. For example, to find if the port 560 is open or not, do netstat -an |find /i "560" command. The service should listen on 0.0.0.0 not 127.0.0.1.

The article you are referring assumes that you've already started the appropriate services and opened any OS firewall rules on the VM prior to opening the ports in NSG rules. If there is no service running on port 560/561, opening those ports in NSG rule will not help.

Kindly let us know if the above helps or you need further assistance on this issue.

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Answer 2

Do you have a second VM in the same subnet of your Windows 10 VM?
Is the second VM able to connect to the ports 560/561 on the Windows 10 VM?
This is just to make sure the Windows 10 VM is listening on this ports if network traffic is "local".
All network traffic/ports in the same subnet are allowed by default.

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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards
Andreas Baumgarten