mDNS: Multicast Domain Name System

https://en.wikipedia.org/wiki/Multicast_DNS

Responder

Sming provides the :cpp:class:`mDNS::Responder` class to allow applications to advertise themselves on the local network.

To use:

1. Add COMPONENT_DEPENDS += MDNS to your application componenent.mk file.

2. Add these lines to your application:

   #include <Mdns/Responder.h>
   
   static mDNS::Responder responder;
   
   // Call when IP address has been obtained
   void startmDNS()
   {
      responder.begin(F("myhostname");
   }

This will advertise the device as myhostname.local.

To provide a custom service, implement a :cpp:class:`mDNS::Service` class and call :cpp:func:`mDNS::Responder::addService`.

See the :sample:`UdpServer_mDNS` sample application.

Discovery

This library also provides support for device discovery using a separate set of classes, based on the :cpp:class:`mDNS::Server`. See :sample:`Basic_Mdns` for an example.

Testing

For linux, you can use avahi to perform mDNS queries and confirm output is as expected:

sudo apt install avahi
avahi-browse --all -r

References

• Multicast DNS RFC6762 https://tools.ietf.org/html/rfc6762
• Zero-configuration networking (DNS-SD) https://en.wikipedia.org/wiki/Zero-configuration_networking
• DNS-Based Service Discovery https://tools.ietf.org/html/rfc6763
• DNS record types https://en.wikipedia.org/wiki/List_of_DNS_record_types
• Domain Names: Implementation and Specification https://tools.ietf.org/html/rfc1035

API Documentation

.. doxygennamespace:: mDNS