CircleCI builds are currently run mainly from AWS East and West. Google Cloud Platform and additional services may be used in the future. For this reason, we can't give a list of IP addresses that our cloud system will use.
Some options you might like to try instead of whitelisting:
- Set a password or SSH key access for connecting to the machine you need.
- Use a jumphost that you connect to from CircleCI which is whitelisted for the external server
- Consider our Server solution (https://circleci.com/enterprise/) where you can specify your own IP ranges.