如何白名单IBM Cloud Functions部署位置的访问地址？

Great question! When working with IBM Cloud Functions (now integrated under IBM Cloud Code Engine's serverless tools) and needing to configure a target server's whitelist for your function's outbound REST calls, here's what you need to know specifically for the US South region:

IP Ranges to Whitelist #

IBM publishes public IP ranges for all its cloud regions, including US South (region code: us-south). These are the addresses your function will use when making outbound requests.

• You can fetch the US South-specific IP ranges using the IBM Cloud CLI with this command:

  ibmcloud ip-ranges --output json | jq '.regions[] | select(.name=="us-south")'
  

  This filters the full global IP range list to only show the ranges associated with US South, which includes the outbound addresses used by Cloud Functions.
• If you don’t have the CLI set up, you can also access this information through the IBM Cloud Console’s network section (look for "IP Ranges" under the VPC or Network services menu) to get the same list of ranges.

Hostnames/Domains #

Unlike some services, IBM Cloud Functions doesn’t use a static, dedicated hostname for outbound requests. Traffic originates directly from the IP ranges noted above. If your target server supports reverse DNS whitelisting, you could look up PTR records for the IPs in the US South range, but this isn’t recommended—IPs in these ranges are shared across multiple IBM Cloud services, so reverse DNS might not be consistent or reliable for your use case.

Additional Notes #

• Private Endpoints: If you’re using private endpoints for your Cloud Functions deployment, outbound traffic will use IBM’s private network IP ranges instead of public ones. Use the same CLI command but filter for private ranges (adjust the jq query to target .private_ips instead of the default public ranges).
• Updates: IBM occasionally updates these IP ranges, so it’s a good practice to automate checks (e.g., a weekly script running the CLI command) to keep your whitelist current and avoid unexpected access issues.

内容的提问来源于stack exchange，提问作者CharekC