MAC addresses of the source machine aren't available beyond the local network. Many systems do have velocity limits. They're somewhat difficult to implement an

MAC addresses of the source machine aren't available beyond the local network. Many systems do have velocity limits. They're somewhat difficult to implement and can have false positives, as you mention, for corporate gateways. An article about an industrial-strength rate limiting system is at https://brandur.org/redis-cluster https://brandur.org/redis-cluster.