CircleCI

CircleCI publishes a JSON file of IP ranges for macOS builds, jobs using the IP ranges feature, and core cloud services. Use their documentation for feature scope, DNS-based listings, and change policy.

CircleCI - official IP ranges (JSON) Official feed

https://circleci.com/docs/ip-ranges-list.json

Documentation

CircleCI - restrict pipeline traffic (IP ranges)

Verify current addresses against CircleCI’s DNS aggregate.

dig all.knownips.circleci.com A +short