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FANUC Alarm DNET-104 — WARN Duplicate MAC Id error

FANUC DNET-104 (“WARN Duplicate MAC Id error”): The specified device has the same MAC Id as another device on the network. First check: Check that no other devices have the same MAC Id, particularly those connected to a different master on the same network.

Updated 2026-09-17 · LogrobotLM reference

Description

The specified device has the same MAC Id as another device on the network.

Remedy

Check that no other devices have the same MAC Id, particularly those connected to a different master on the same network. Change the MAC Id of the offending device at both the device and on the Device List, and attempt to bring it on-line. If the problem persists, cold start the controller and try again. If the problem continues, document the events that led to the error and call your FANUC Robotics technical representative.

Related codes

DNET-102WARN Invalid board MAC IdDNET-103WARN Invalid board baud rateDNET-105WARN Duplicate device errorDNET-106WARN Device not found error

Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →