ESP32 mDNS Query Returns No Results

In this tutorial, you'll learn about ESP32 mDNS Query Returns No Results. We cover key concepts, practical examples, and best practices.

The Problem

ESP32 queries mDNS for other devices on the network but finds nothing.

Quick Fix

Wrong

int n = MDNS.queryService("http", "tcp");
if (n == 0) Serial.println("No services found");

No services found (but other devices are online and advertising mDNS).

Right

MDNS.addService("http", "tcp", 80);
delay(2000);
int n = MDNS.queryService("http", "tcp");
Serial.printf("Found %d services\n", n);
for (int i = 0; i < n; i++) {
  Serial.printf("%s:%d\n", MDNS.hostname(i).c_str(), MDNS.port(i));
}

Found 2 services
raspberrypi.local:80
server-room.local:3000

Prevention

Wait 2 seconds after starting mDNS before querying. Use exact service type and protocol. Verify target devices have mDNS enabled. Check that both devices are on the same VLAN/subnet.

DodaTech engineers apply these same patterns across Doda Browser, DodaZIP, and Durga Antivirus Pro for production IoT reliability.

FAQ