Curated OT / IT references

The Field Library.

Official specifications, vendor support and practical network references worth keeping close. No scraped articles. No affiliate links. Just useful starting points for real protocol work.

01Protocol references 02Vendor engineering support 03Network evidence 04OT security guidance

01 / REFERENCE SET

Protocol references

Start with the organisation that owns or maintains the technology.

OPC UA

OPC Foundation

OPC UA Online Reference

Browse the OPC UA specifications, services, information models and security definitions.

OPC UA

OPC Foundation

OPC UA Companion Specifications

Find industry and machine-specific information models built on top of OPC UA.

EIP / CIP

ODVA

EtherNet/IP Technology Overview

Check the official EtherNet/IP architecture, CIP relationship and implementation resources.

MODBUS

Modbus Organization

Modbus Specifications

Download the current Modbus application protocol and implementation guidance.

SNMP

IETF · RFC 3411

SNMP Management Frameworks

Understand the architecture and terminology behind SNMP management systems.

02 / REFERENCE SET

Vendor engineering support

Use documentation that matches the exact product family and firmware in front of you.

MITSUBISHI

Mitsubishi Electric

Factory Automation Downloads

Find manuals, technical bulletins, software, CAD data and sample libraries by product.

ROCKWELL

Rockwell Automation

Product Compatibility & Download Center

Check product versions, compatibility, lifecycle information and available downloads.

SIEMENS

Siemens

Industry Online Support

Search manuals, FAQs, product notes, downloads and support articles.

03 / REFERENCE SET

Network evidence

Useful when the problem is somewhere between “the host responds” and “the protocol works.”

PACKETS

Wireshark Foundation

Wireshark User’s Guide

Learn capture setup, display filters, protocol inspection and evidence export workflows.

PORTS

IANA

Service Name and Port Registry

Verify officially registered TCP and UDP service names and port numbers.

DISCOVERY

Nmap Project

Nmap Reference Guide

Reference host discovery, port scanning and service detection options before a bounded test.

04 / REFERENCE SET

OT security guidance

Baseline guidance for designing, operating and troubleshooting industrial environments safely.

NIST

NIST · SP 800-82 Rev. 3

Guide to Operational Technology Security

Use a current, vendor-neutral reference for OT security architecture and risk management.

CISA

ICS Recommended Practices

Find practical defensive guidance and recommended practices for control systems.

KEEP IT USEFUL

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