Part 3 of 3: What the honeypot findings mean for defenders, how to reduce the attack surface, and which behaviours are worth monitoring when ICS and IoT services are exposed. Part 3 of 3: What the honeypot findings mean for defenders, how to reduce the attack surface, and which behaviours are worth monitoring when ICS and IoT services are exposed. Part 1 covered the build: a cloud VPS, a fictional HelioControl energy persona, public decoys for SSH, Telnet, HTTP, HTTPS, MQTT, Modbus, S7Comm, and BACnet, and a private Loki/Grafana monitoring plane. Part 2 covered what showed up after the system went online: mostly commodity internet automation, plus a smaller but important tail of protocol-aware ICS and IoT reconnaissance. Part 1 Part 2 This final part is about the defensive question. If an exposed energy-themed honeypot is found quickly, brute-forced continuously, probed for common web mistakes, and asked protocol-valid Modbus identity questions, what should a real operator do differently? The answer is more ordinary than the threat model sometimes suggests. The controls that stop the commodity flood are also the controls that reduce the targeted tail. You do not need perfect attribution before you can defend well. You need to know what is exposed, keep fragile protocols away from the public internet, remove default access paths, contain outbound abuse, and log the behaviours that matter. The approach in this article is to defend the structure first, then tune detections around the specific behaviours the honeypot saw. The Threat Model the Data Supports The dataset does not support a story about confirmed energy-sector targeting or process manipulation. It supports a more practical and more common one. Public services were discovered within the first live hour. SSH and Telnet carried most of the volume as default and weak credentials were tested continuously. Web