Google publishes the complete list of outbound IP address ranges that it makes available to users on the internet in goog.json.

Google also publishes a list of global and regional external IP addresses ranges available for customer's Google Cloud resources in cloud.json.

Goal of this script is to identify & show the available CIDRs. To learn more about CIDR check at Link

This script is Python 2 (2.7) and 3 (3.6+) compatible.

Python 2.7 & Python 3.6, 3.7, 3.8, 3.9, 3.10

(Optional) Using virtualenv is an effective to ensure script executions without disturbing your existing local environment. Run the following steps to execute the script safely in a Python 3 environment—a similar technique can be used to run it in Python 2:

pip3 install virtualenv
virtualenv --python python3 py3
source py3/bin/activate

To install the requirements

pip install -r requirements.txt

To run the script

python cidr.py

To exit the virtualenv

deactivate

Create a python virtual environment py3

pip3 install virtualenv
virtualenv --python python3 py3

Install requirements and run testcases

source py3/bin/activate
pip install -r requirements.txt -r dev-requirements.txt
python3 -m pytest
# Test for multiple python version
nox

If you're on a Mac where local SSH certificates haven't been installed yet, you may get this error:

(py3) $ python cidr.py
ERROR: Invalid HTTP response from https://www.gstatic.com/ipranges/goog.json
ERROR: Invalid HTTP response from https://www.gstatic.com/ipranges/cloud.json
IP ranges for Google APIs and services default domains:
Traceback (most recent call last):
  File "/tmp/networking-tools-python/tools/cidr/cidr.py", line 65, in <module>
    main()
  File "/tmp/networking-tools-python/tools/cidr/cidr.py", line 60, in main
    for ip in (cidrs["goog"] - cidrs["cloud"]).iter_cidrs():
TypeError: unsupported operand type(s) for -: 'NoneType' and 'NoneType'

If this is the case, run the command shown below (Python 3.9 example):

(py3) $ open /Applications/Python\ 3.9/Install\ Certificates.command

A window will pop up, run a few commands, then automatically close. Once that happens, you should be able to run python cidr.py again and have it work. If you don't use the command-line, then follow these instructions from your computer screen.