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mDSN

mDNS (Multicast DNS)

Multicast DNS (mDNS) is a protocol that allows devices on a local network to perform DNS-like operations without requiring a dedicated DNS server. It enables the resolution of hostnames to IP addresses within small networks using multicast IP address 224.0.0.251 and UDP port 5353.

Key Points:

  • Local Network Name Resolution: mDNS is primarily used for resolving hostnames to IP addresses within the same local network segment, making it easier to discover devices and services without a central DNS server.
  • Zero Configuration: mDNS is part of the Zeroconf (Zero Configuration Networking) suite, allowing devices to automatically configure themselves and discover other devices without manual setup.
  • Multicast Communication: It uses multicast communication to send DNS queries to all devices on the local network, and the device with the matching hostname responds with its IP address.
  • Compatibility: mDNS is widely implemented in consumer and enterprise devices, often seen in technologies like Apple's Bonjour, which uses mDNS for service discovery.

Technical Details:

  • Multicast Address: 224.0.0.251
  • Port: UDP 5353
  • Standards: Defined in RFC 6762

In summary, mDNS provides a way for devices to discover and communicate with each other on a local network without the need for manual configuration or a central DNS server, making it an essential protocol for modern networking environments.