Cannot bind to external IP address of google compute engine VM instance

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I am trying to test a simple client-server setup between my laptop and my google compute engine instance using python. The setup works fine between 2 laptops. But when I run the server program in my VM instance I get the following error after calling the bind command: "socket.error: [Errno 99] Cannot assign requested address"

I am trying to bind to the external IP address so I can receive data from an external device.

Here is the code snippet

import socket

s = socket.socket()

port = 12345

s.bind(('xxx.xxx.xxx.xxx',port))

Can anyone please tell me why I can't bind to the external IP address. I have tried to find the answer in Google's docs and via online searches but to no avail. I am new to this and don't really even know what info to post that would help in troubleshooting. Thanks in advance.

Here are my firewall rules Firewall rules

google-compute-engine google-cloud-platform python
1 Answers

Google Cloud's networking has a distinction between internal and external IP addresses. In particular, a GCE VM won't actually have an interface with the externally visible IP address -- the cloud infrastructure handles the translation outside of the instance.

You need to bind to the internal IP address for your instance, and GCP's networking infrastructure will take care of the routing for you, assuming such routing is allowed by your VPC firewall configuration.

Note: As provided, your current firewall configuration does not have a rule that will allow ingress on the 12345 port and you will need to add this and ensure it applies to this particular instance (either via a target tag which is applied to the instance, or by applying the rule to all targets in your network)

You might also consider using 0.0.0.0 (or INADDR_ANY) which in python is just the empty string. So this should also work for you (again, assuming the correct firewall configuration):

import socket

s = socket.socket()
port = 12345
s.bind(('',port))
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