Port 1883 — MQTT

TCP · Port 1883/TCP is used for the Message Queuing Telemetry Transport (MQTT) protocol, a lightweight messaging protocol for IoT devices. MQTT enables efficient and reliable communication between devices over low-bandwidth networks. This port/service is critical in IoT security as it allows for device-to-cloud and device-to-device communication, making it vulnerable to attacks such as message tampering and replay attacks.

Port Number: 1883
Service Name: MQTT
Protocol: TCP
Common Software: Mosquitto, EMQ X

Security Notes

Review IANA registry for port 1883 usage. Apply principle of least privilege - only open ports that are required.

FAQ

What is port 1883 used for?

Port 1883 is used for MQTT. Port 1883/TCP is used for the Message Queuing Telemetry Transport (MQTT) protocol, a lightweight messaging protocol for IoT devices. MQTT enables efficient and reliable communication between devices over low-bandwidth networks. This port/service is critical in IoT security as it allows for device-to-cloud and device-to-device communication, making it vulnerable to attacks such as message tampering and replay attacks. Common software: Mosquitto, EMQ X.

Is port 1883 dangerous to leave open?

Review IANA registry for port 1883 usage. Apply principle of least privilege - only open ports that are required.

How do I check if port 1883 is open?

Use nmap: nmap -p 1883 <target> or check locally: ss -tlnp | rg 1883