ESP32 static/fix IP address

In this tutorial, you will learn how to fix the IP address of ESP32.  To IP address of ESP32 static, we need to make a few changes in the network to which your board is connected. You must be wondering what is meant by assigning a static or fix IP address to EP32. When you create a web server with ESP32, we always access the web server through an IP address. But whenever we restart or reboot ESP32, we possibly get a new IP address. WiFi network usually assigns a new IP address to ESP32 board. Therefore, we can assign a static or fix IP address to our board. Shortly, you will be able to do fix the IP address of ESP32 with a very easy method.

ESP32 Fix or Static IP Address

How to assign static/Fix IP Address

For an illustration of how to assign a static IP address to ESP32, we use the example of an ESP32 Web server with DHT11/DHT22.  We will use the same sketch use in that tutorial except adding the functionality of assigning fix IP address.  In order to understand the code given below, I suggest you check ESP32 Web server with DHT11/DHT22 interfacing tutorial. In this tutorial, I will only explain those functions that are used for assigning fix IP address.

#include <WiFi.h>
#include <Wire.h>
#include "DHT.h"

// Uncomment one of the lines below for whatever DHT sensor type you're using!
//#define DHTTYPE DHT11 // DHT 11
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
#define DHTTYPE DHT22 // DHT 22 (AM2302), AM2321
//DHT Sensor;
uint8_t DHTPin = 4;


// Initialize DHT sensor.
DHT dht(DHTPin, DHTTYPE);

float Temperature;
float Humidity;

// Replace with your network credentials
const char* ssid = "Enter your WiFi name here"; // Enter SSID here
const char* password = "Enter your WiFi password herer"; //Enter Password here

// Set web server port number to 80
WiFiServer server(80);

// Variable to store the HTTP request
String header;


// it wil set the static IP address to 192, 168, 1, 184
IPAddress local_IP(192, 168, 1, 184);
//it wil set the gateway static IP address to 192, 168, 1,1
IPAddress gateway(192, 168, 1, 1);

// Following three settings are optional
IPAddress subnet(255, 255, 0, 0);
IPAddress primaryDNS(8, 8, 8, 8); 
IPAddress secondaryDNS(8, 8, 4, 4);

void setup() {
Serial.begin(115200);
pinMode(DHTPin, INPUT);
dht.begin();

// This part of code will try create static IP address
if (!WiFi.config(local_IP, gateway, subnet, primaryDNS, secondaryDNS)) {
Serial.println("STA Failed to configure");
}

// Connect to Wi-Fi network with SSID and password
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
// Print local IP address and start web server
Serial.println("");
Serial.println("WiFi connected.");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
server.begin();
}

void loop()
{
Temperature = dht.readTemperature(); // Gets the values of the temperature
Humidity = dht.readHumidity(); // Gets the values of the humidity 
WiFiClient client = server.available(); // Listen for incoming clients

if (client) 
{ // If a new client connects,

String request = client.readStringUntil('\r'); 
client.println("HTTP/1.1 200 OK");
client.println("Content-type:text/html");
client.println("Connection: close");
client.println();

// Display the HTML web page
client.println("<!DOCTYPE html><html>");
client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
client.println("<link rel=\"icon\" href=\"data:,\">");
client.println("<meta http-equiv=\"refresh\" content=\"2\">");
client.println("<script>\n");
client.println("setInterval(loadDoc,200);\n");
client.println("function loadDoc() {\n");
client.println("var xhttp = new XMLHttpRequest();\n");
client.println("xhttp.onreadystatechange = function() {\n");
client.println("if (this.readyState == 4 && this.status == 200) {\n");
client.println("document.getElementById(\"webpage\").innerHTML =this.responseText}\n");
client.println("};\n");
client.println("xhttp.open(\"GET\", \"/\", true);\n");
client.println("xhttp.send();\n");
client.println("}\n");
client.println("</script>\n)"); 
// CSS to style the table

client.println("<style>body { text-align: center; font-family: \"Arial\", Arial;}");
client.println("table { border-collapse: collapse; width:40%; margin-left:auto; margin-right:auto;border-spacing: 2px;background-color: white;border: 4px solid green; }");
client.println("th { padding: 20px; background-color: #008000; color: white; }");
client.println("tr { border: 5px solid green; padding: 2px; }");
client.println("tr:hover { background-color:yellow; }");
client.println("td { border:4px; padding: 12px; }");
client.println(".sensor { color:white; font-weight: bold; background-color: #bcbcbc; padding: 1px; }"); 

// Web Page Heading
client.println("</style></head><body><h1>ESP32 Web Server Reading sensor values</h1>");
client.println("<h2>DHT11/DHT22</h2>");
client.println("<h2>Microcontrollerslab.com</h2>");
client.println("<table><tr><th>MEASUREMENT</th><th>VALUE</th></tr>");
client.println("<tr><td>Temp. Celsius</td><td><span class=\"sensor\">");
client.println(dht.readTemperature());
client.println(" *C</span></td></tr>"); 
client.println("<tr><td>Temp. Fahrenheit</td><td><span class=\"sensor\">");
client.println(1.8 * dht.readTemperature() + 32);
client.println(" *F</span></td></tr>"); 
client.println("<tr><td>Humidity</td><td><span class=\"sensor\">");
client.println(dht.readHumidity());
client.println(" %</span></td></tr>"); 
client.println("</body></html>");

client.println();
Serial.println("Client disconnected.");
Serial.println("");
}
}
  • Now copy this code to your Arduino IDE.
  • Before uploading this code to ESP32 board, you need to enter SSID name and Password in these lines that are your WiFi name and password.
// change it with your WiFi use name and password 
const char* ssid = "Enter your WiFi name here"; // Enter SSID here
const char* password = "Enter your WiFi password herer"; //Enter Password here
  • As mentioned earlier, all code is the same as used in DHT11 interfacing with ESP32 tutorial except the code which adds the functionality of fixing the IP address of ESP32. Now, we will see how to add this functionality?

Code of Assigning Static IP address to ESP32

  • Above the setup() function, these lines are used to assign a static IP address to the ESP32 development board.
  • PAddress local_IP() functions assign the IP address of 192, 168, 10, 47 through a gateway of 192, 168, 2 2.
  • You can choose the IP address and gateway address to whatever value you want according to the available list of IP addresses in your local area network.
  • Last three lines set the subnet, primary DNS and secondary DNS for network settings. I recommend you do not change these values unless you really understand the concepts of networking.
  • primaryDNS and secondaryDNS functions are optional here. you can delete them if you want.
// it wil set the static IP address to 192, 168, 10, 47
IPAddress local_IP(192, 168, 10, 47);
//it wil set the gateway static IP address to 192, 168, 2,2
IPAddress gateway(192, 168, 2 ,2);

// Following three settings are optional
IPAddress subnet(255, 255, 0, 0);
IPAddress primaryDNS(8, 8, 8, 8); 
IPAddress secondaryDNS(8, 8, 4, 4);
  • Inside the setup() function, WiFi.config() function used to fix the IP address according to above given parameters such as local_IP, gateway, subnet, primaryDNS, secondaryDNS.
  • If the IP address is available in your local area network, it will assign this IP address.
  • Otherwise, you will see the message “TA Failed to configure” on the serial monitor.
// This part of code will try create static IP address
if (!WiFi.config(local_IP, gateway, subnet, primaryDNS, secondaryDNS)) 

{
Serial.println("STA Failed to configure");
}
  • Now your ESP32 sketch is ready to be uploaded.
  • Click on the upload button in your Arduino IDE.
  • After uploading code, open serial monitor of Arduino IDE.
  • you will see this message on a serial monitor which show you the IP address you assigned. ESP32 Fix or Static IP Address in Arduino IDE
  • This is the same IP address which we mentioned inside the sketch and local area network has assigned the same IP address to ESP32 board.

Now even if you restart or reboot your ESP32 board, you will always get the same IP address and you can access ESP32 web server with the same IP address.

Static IP address library

This section provides details on functions used to assign static IP.

  • WiFi.config(): This functions used to configure a fix IP address and also modify the DNS, gateway, and subnet addresses for ESP32 board.  WiFi.begin() function automatically assigns an IP address to devices from the available list of IP addresses in your network.
  • If you call WiFi.config() before WiFi.begin(), it will force the .begin to assign IP address according to define IP address inside .config().

I hope you enjoyed this tutorial, you may also like to check other ESP32 tutorials and projects:

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7 thoughts on “ESP32 static/fix IP address”

    • you need to check your router settings. There is nothing wrong with the program. Your router settings are not supporting static IP address

      Reply

      • It might be worth to make some changes at the router settings? I had been modified my own a long time ago as follow: reduced the DHCP address range leaving a certain range for fixed Ip addressed devices. My default DHCP range was 192.168.1.1/24 – 192.168.1.253/24 while the default gateway (router’s IP) 192.168.1.254/24 and the reduced DHCP range is 192.168.1.1/24 – 192.168.1.200/24. (If somebody don’t know what the /24 means: it’s referring to the (default) masking value as 255.255.255.0

        Reply

    • I had the same problem. As a matter fact, there is an issue with the WiFi library that had to be solved but apparently it is not.
      The workaround I have implemented and it works is the following:
      1. comment the following code:
      while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(“.”);
      }
      2. replace it with:
      delay (15000);

      That means the code does not wait for the WL_CONNECTED status, instead, it waits for 15 seconds and afterwards, it considers connected. It works well most of the times, won’t work well in cases of outages when the router needs some time to boot up.

      Reply

  3. Is it the value of “IPAddress subnet(255, 255, 0, 0);” right? The fix local IP address here is a Class C, where the default subnet mask should be 255.255.255.0

    Reply

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