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DNS

The internet's phone book: it turns a name like broker.example.com into an IP address.

The Domain Name System resolves names to records such as A (IPv4) and AAAA (IPv6) addresses through a hierarchy of servers, with answers cached for their time to live.

Examples

  • Firmware names its broker as mqtt.example.com; a DNS query to port 53 turns that name into an IP address.

  • Because a DNS answer has a time to live, the sensor must look the broker's name up again rather than keep its address forever.

See also

DHCP IP address port
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