jpg0 / dhcp2mqtt

Scapy script to relay DHCP request info to MQTT

DHCP2MQTT

Just a simple script to listen for DHCP multicast discover packets and broadcast over MQTT. Intended to be integrated into HomeAssistant for faster presence detection. Most network detection relies on polling router client lists, and this will fire as soon as your device connects to wifi.

Running in Docker

Container must be run with host networking in order to receive multicast packets.

docker run --rm --net=host -e MQTT_HOST=mqtt.server.com -e MACS_TO_MONITOR=ab:cd:e1:23:45:67,aa:aa:aa:aa:aa:aa blakeblackshear/dhcp2mqtt:latest

Environment Variables

Name	Required	Default	Description
MACS_TO_MONITOR	Yes		Comma separated list of mac addresses to watch
MQTT_HOST	Yes		Host or IP of MQTT server
MQTT_PORT	No	1883	Port of MQTT server
MQTT_USER	No		MQTT user if set
MQTT_PASS	No		MQTT password if set
MQTT_TOPIC_PREFIX	No	network/dhcp	Topic prefix for MQTT messages
MQTT_CLIENT_ID	No	dhcp2mqtt	Client id for mqtt connection

MQTT Messages

Messages are posted to MQTT when a discover packet is detected:

network/dhcp/ab:cd:e1:23:45:67 discover