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lib/esp8266_mdns/README.md

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+# esp8266_mdns
+mDNS queries and responses on esp8266.
+Or to describe it another way: An mDNS Client or Bonjour Client library for the esp8266.
+
+This library aims to do the following:
+ 1. Give access to incoming mDNS packets and decode Question and Answer Records for commonly used record types.
+ 2. Allow Question and Answer Records for commonly used record types to be sent.
+
+Future goals:
+ 1. Dynamic buffer paging. Currently one page is read from the network. If the mDNS packet is larger than that page size, any responses in the remainder are lost. (See MAX_PACKET_SIZE in mdns.h.)
+ 2. Automatic replies to incoming Questions.
+ 3. Automatic retries when sending packets according to rfc6762.
+
+Requirements
+------------
+- An Espressif [ESP8266](http://www.esp8266.com/) WiFi enabled SOC.
+- The [ESP8266 Arduino](https://github.com/esp8266/Arduino) environment.
+- ESP8266WiFi library.
+- MDNS support in your operating system/client machines:
+  - For Mac OSX support is built in through Bonjour already.
+  - For Linux, install [Avahi](http://avahi.org/).
+  - For Windows, install [Bonjour](http://www.apple.com/support/bonjour/).
+
+Usage
+-----
+Find information on how to add a library to your Arduino IDE [here](https://www.arduino.cc/en/Guide/Libraries).
+
+The file [mdns.h](https://github.com/mrdunk/esp8266_mdns/blob/master/mdns.h) is well commented. Try looking there for information on specific methods.
+
+To add a simple mDNS listener to an Aruino sketch which will display all mDNS packets over the serial console try the following:
+
+```
+// This sketch will display mDNS (multicast DNS) data seen on the network.
+
+#include <ESP8266WiFi.h>
+#include "mdns.h"
+
+// When an mDNS packet gets parsed this optional callback gets called.
+void packetCallback(const mdns::MDns* packet){
+  packet->Display();
+  packet->DisplayRawPacket();
+}
+
+// When an mDNS packet gets parsed this optional callback gets called once per Query.
+// See mdns.h for definition of mdns::Query.
+void queryCallback(const mdns::Query* query){
+  query->Display();
+}
+
+// When an mDNS packet gets parsed this optional callback gets called once per Query.
+// See mdns.h for definition of mdns::Answer.
+void answerCallback(const mdns::Answer* answer){
+  answer->Display();
+}
+
+// Initialise MDns.
+// If you don't want the optional callbacks, just provide a NULL pointer as the callback.
+mdns::MDns my_mdns(packetCallback, queryCallback, answerCallback);
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  Serial.begin(115200);
+
+  // setting up Station AP
+  WiFi.begin("your_wifi_ssid", "your_wifi_password");
+
+  // Wait for connect to AP
+  int tries = 0;
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+    tries++;
+    if (tries > 30) {
+      break;
+    }
+  }
+  Serial.println();
+}
+
+void loop() {
+  my_mdns.loop();
+}
+```
+
+A more complete example which sends an mDNS Question and parses Answers is available in esp8266_mdns/examples/mdns_test/ .
+
+Troubleshooting
+---------------
+Run [Wireshark](https://www.wireshark.org/) on a machine connected to your wireless network to confirm what is actually in flight.
+The following filter will return only mDNS packets: ```udp.port == 5353``` .
+Any mDNS packets seen by Wireshark should also appear on the ESP8266 Serial console.