API Reference: Implementing OT Network Traffic Analysis with Nozomi
Nozomi Guardian REST API
| Endpoint |
Method |
Description |
/api/v1/alerts |
GET |
Retrieve security alerts |
/api/v1/assets |
GET |
Get discovered asset inventory |
/api/v1/nodes |
GET |
Get network nodes |
/api/v1/links |
GET |
Get network links/connections |
/api/v1/sessions |
GET |
Get active network sessions |
/api/v1/queries |
POST |
Execute N2OS query |
/api/v1/health |
GET |
Sensor health status |
Authentication
# Bearer token
curl -s -k -H "Authorization: Bearer <token>" https://guardian/api/v1/assets
# API key (Vantage)
curl -s -H "X-Api-Key: <key>" https://vantage.nozominetworks.com/api/v1/assets
N2OS Query Language
-- Find all PLCs
alerts | where type == plc
-- Find new connections in last 24h
sessions | where first_seen > ago(24h) | sort by bytes desc
-- Find Modbus traffic
sessions | where protocol == modbus | select src_ip, dst_ip, function_code
Supported OT Protocols
| Protocol |
Detection |
DPI Support |
| Modbus/TCP |
Full |
Function code analysis |
| S7comm |
Full |
Block read/write detection |
| EtherNet/IP (CIP) |
Full |
Service code inspection |
| DNP3 |
Full |
Object group parsing |
| OPC UA |
Full |
Service/node inspection |
| BACnet |
Full |
Object/property analysis |
| PROFINET |
Full |
Cyclic/acyclic detection |
| IEC 60870-5-104 |
Full |
ASDU type parsing |
Alert Risk Levels
| Level |
Score Range |
Response |
| Critical |
9.0 - 10.0 |
Immediate investigation |
| High |
7.0 - 8.9 |
Investigate within 4 hours |
| Medium |
4.0 - 6.9 |
Investigate within 24 hours |
| Low |
0.1 - 3.9 |
Review during next shift |
Sensor Deployment
| Mode |
Use Case |
| SPAN/Mirror |
Switch mirror port monitoring |
| TAP |
Network TAP for full-duplex capture |
| Smart Polling |
Active query for asset enrichment |
References