From 00065ac3471b9e1ffdc1be34e3771abbbd29e416 Mon Sep 17 00:00:00 2001
From: Ivan Grokhotkov <ivan@espressif.com>
Date: Sun, 12 Jun 2016 14:44:15 +0800
Subject: [PATCH] Allow DHCP client to be re-enabled using WiFi.config(0U, 0U,
 0U) (#1896)

---
 libraries/ESP8266WiFi/src/ESP8266WiFiSTA.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libraries/ESP8266WiFi/src/ESP8266WiFiSTA.cpp b/libraries/ESP8266WiFi/src/ESP8266WiFiSTA.cpp
index 0a6a4c9be..918866727 100644
--- a/libraries/ESP8266WiFi/src/ESP8266WiFiSTA.cpp
+++ b/libraries/ESP8266WiFi/src/ESP8266WiFiSTA.cpp
@@ -212,6 +212,12 @@ bool ESP8266WiFiSTAClass::config(IPAddress local_ip, IPAddress gateway, IPAddres
     info.gw.addr = static_cast<uint32_t>(gateway);
     info.netmask.addr = static_cast<uint32_t>(subnet);
 
+    if (local_ip == 0U && gateway == 0U && subnet == 0U) {
+        _useStaticIp = false;
+        wifi_station_dhcpc_start();
+        return true;
+    }
+
     wifi_station_dhcpc_stop();
     if(wifi_set_ip_info(STATION_IF, &info)) {
         _useStaticIp = true;