Marine Protocol Guides
Requirement: To enforce Conduits (Step 03), you must first understand the “Language” of the assets. This module maps common maritime protocols (NMEA, Modbus, J1939) to their technical ports.
Marine OT environments are a hybrid of standard Ethernet traffic and specialized industrial serial protocols. Identifying these data flows is critical for creating accurate firewall Access Control Lists (ACLs).
1. Common Vessel Protocols
Dominated by NMEA 0183 (Serial) and NMEA 2000 (CAN bus). These are often bridged to Ethernet via Gateways.
Commonly uses Modbus TCP (Port 502) or J1939. These protocols lack built-in encryption.
2. Port & Service Mapping
| Protocol | Standard Port | Security Risk |
|---|---|---|
| Modbus TCP | 502 | No Auth; vulnerable to injection. |
| NMEA over IP | 10110 (Typical) | Cleartext data; GPS spoofing risk. |
| Siemens S7 | 102 | Proprietary; requires DPI. |
Protocols Defined?
Step 1 Complete. Now that you understand the “languages” your systems speak, it is time to capture live data to verify your network map.