mDNS example

Shows how to use mDNS to advertise and query services and hosts

Example workflow

mDNS is initialized with host name and instance name defined through the project configuration and _http._tcp service is added to be advertised
A delegated host esp32-delegated._local is added and another _http._tcp service is added for this host.
WiFi STA is started and trying to connect to the access point defined through the project configuration
The system event handler is used to pass the network events to mDNS so the service is aware when the interface comes up or down
GPIO0 (BOOT Button) is initialized as pulled-up input that can be monitored for button press
Example task is started to check if the button is pressed so it can execute the mDNS queries defined

Configure the project

Open the project configuration menu (idf.py menuconfig)
Configure Wi-Fi or Ethernet under "Example Connection Configuration" menu
Set mDNS Hostname as host name prefix for the device and its instance name in mDNS Instance Name
Disable Resolve test services to prevent the example from querying defined names/services on startup (cause warnings in example logs, as illustrated below)

Build and Flash

Build the project and flash it to the board, then run monitor tool to view serial output:

Plaintext

idf.py -p PORT flash monitor

Wait for WiFi to connect to your access point
You can now ping the device at [board-hostname].local, where [board-hostname] is preconfigured hostname, esp32-mdns by default.
You can also browse for _http._tcp on the same network to find the advertised service
Pressing the BOOT button will start querying the local network for the predefined in check_button hosts and services
Note that for purpose of CI tests, configuration options of MDNS_RESOLVE_TEST_SERVICES and MDNS_ADD_MAC_TO_HOSTNAME are available, but disabled by default. If enabled, then the hostname suffix of last 3 bytes from device MAC address is added, e.g. esp32-mdns-80FFFF, and a query for test service is issued.

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example Output