.. zephyr:code-sample:: mdns-responder
   :name: mDNS responder
   :relevant-api: net_core dns_sd bsd_sockets

   Listen and respond to mDNS queries.

Overview
********

This application will wait mDNS queries for a pre-defined hostname and
respond to them. The default hostname is **zephyr** and it is set in the
:file:`prj.conf` file.

Requirements
************

- :ref:`networking_with_host`

- avahi or similar mDNS capable application that is able to query mDNS
  information.

Building and Running
********************

Build and run the mdns-responder sample application like this:

.. zephyr-app-commands::
   :zephyr-app: samples/net/mdns_responder
   :board: <board to use>
   :conf: <config file to use>
   :goals: build
   :compact:

After the mdns-responder sample application is started, it will await queries
from the network.

Open a terminal window in your host and type:

.. code-block:: console

    $ avahi-resolve -4 -n zephyr.local

If the query is successful, then following information is printed:

.. code-block:: console

    zephyr.local	192.0.2.1

For a IPv6 query, type this:

.. code-block:: console

    $ avahi-resolve -6 -n zephyr.local

If the query is successful, then following information is printed:

.. code-block:: console

    zephyr.local	2001:db8::1

Lastly, resolve services using DNS Service Discovery:

.. code-block:: console

    $ avahi-browse -t -r _zephyr._tcp

If the query is successful, then the following information is printed:

.. code-block:: console

    +   zeth IPv6 zephyr                                        _zephyr._tcp         local
    =   zeth IPv6 zephyr                                        _zephyr._tcp         local
       hostname = [zephyr.local]
       address = [192.0.2.1]
       port = [4242]
       txt = []