How to open a specific port such as 9090 in Google Compute Engine

Question

I have 2 Google Compute Engine instances and I want to open port 9090 in both the instances. I think we need to add some firewall rules.

Can you tell me how can I

Answer 1

This question is old and Carlos Rojas's answer is good, but I think I should post few things which should be kept in mind while trying to open the ports.

The first thing to remember is that Networking section is renamed to VPC Networking. So if you're trying to find out where Firewall Rules option is available, go look at VPC Networking.

The second thing is, if you're trying to open ports on a Linux VM, make sure under no circumstances should you try to open port using ufw command. I tried using that and lost ssh access to the VM. So don't repeat my mistake.

The third thing is, if you're trying to open ports on a Windows VM, you'll need to create Firewall rules inside the VM also in Windows Firewall along with VPC Networking -> Firewall Rules. The port needs to be opened in both firewall rules, unlike Linux VM. So if you're not getting access to the port from outside the VM, check if you've opened the port in both GCP console and Windows Firewall.

The last (obvious) thing is, do not open ports unnecessarily. Close the ports, as soon as you no longer need it.

I hope this answer is useful.