dynamic WiFi.hostname("newname")

[d-a-v]

Effect of WiFi.hostname("new name") on the network:

My AP runs openwrt with dnsmasq, and I can ping the new hostname as soon as Wifi.hostname("name") is called on the esp.

Sketch:

#include <ESP8266WiFi.h>
#include <PolledTimeout.h>

#ifndef STASSID
#define STASSID "your-ssid"
#define STAPSK  "your-password"
#endif

const char* ssid     = STASSID;
const char* password = STAPSK;

void connect ()
{
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.persistent(false);
  connect();
  WiFi.hostname("chameleon");
  Serial.printf("host name is %s, will change every 20 seconds, ping me !\n", WiFi.hostname().c_str());
}

esp8266::polledTimeout::periodic renew(20000);
int count = 0;

void loop()
{
  if (renew)
  {
    String name = String(++count) + "chameleonchameleonchameleon";
    Serial.printf("setting hostname to: %s\n", name.c_str());
    Serial.printf("ret=%d\n", WiFi.hostname(name));
    Serial.printf("hostname=%s\n", WiFi.hostname().c_str());
  }
}

Logs:

...
setting hostname to: 17chameleonchameleonchameleon
hostname '17chameleonchameleonchameleon' is not compliant with RFC952
ret=0
...

(but esp name stays "nicely" responding to name 17chameleonchameleonchameleon)