If you�ve ever tried running a web server on an ESP32, you�ve likely noticed something annoying�every time you restart your ESP32, the IP address can change, based on what the router decides to assign at the moment. This means you always have to check the serial monitor to find out this new IP address. It�s quite a hassle, right?
This is where static IP addresses come into play. By setting a static IP address, you can access the web server using the same IP address, even after restarting the ESP32. This is also useful to avoid confusion when you have multiple ESP32s connected to your network.
Fortunately, once you know how, it�s a fairly simple and quick process to set a static IP address. We�ll guide you step-by-step on how to set a static IP address on your ESP32. Let�s dive in!
Step 1 � Set Up the Arduino IDE
We will be using the Arduino IDE to program the ESP32, so please ensure you have the ESP32 add-on installed before you proceed:
Step 2 � Connect the ESP32 to your Computer
Use a micro-USB cable to connect your ESP32 board to your computer.
Step 3 � Obtain Current Network Settings
Before setting a static IP, it�s a good practice to check the current network settings (IP, Gateway, Subnet, and DNS) assigned by your router. This information can help avoid IP conflicts. To find out the ESP32�s current IP address and other network settings, you need to upload the following sketch to your ESP32.
Before that, there is one essential modification you need to make. Update the following two variables with your actual WiFi SSID and password.
const char* ssid = "YourNetworkName"; // Enter SSID here
const char* password = "YourPassword"; //Enter Password hereAfter making these changes, go ahead and upload the code.
#include <WiFi.h>
// Replace with your network credentials
const char* ssid = "YourNetworkName"; // Enter SSID here
const char* password = "YourPassword"; //Enter Password here
void setup() {
Serial.begin(115200);
Serial.print("Connecting to ");
Serial.println(ssid);
// Connect to Wi-Fi
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.print(".");
}
Serial.println("");
Serial.println("Connected..!");
Serial.print("Current ESP32 IP: ");
Serial.println(WiFi.localIP());
Serial.print("Gateway (router) IP: ");
Serial.println(WiFi.gatewayIP());
Serial.print("Subnet Mask: " );
Serial.println(WiFi.subnetMask());
Serial.print("Primary DNS: ");
Serial.println(WiFi.dnsIP(0));
Serial.print("Secondary DNS: ");
Serial.println(WiFi.dnsIP(1));
}
void loop() {
}After uploading the code, open the Serial Monitor and set the baud rate to 115200. Then, press the EN button on the ESP32. It may take a few moments to connect to your network, after which it will print the current network settings of the ESP32 to the serial monitor. Take note of these.
Step 4 � Set a Static IP Address
After obtaining the current network settings, you can now set a static IP address.
Modify the sketch below to include the static IP configuration. You will need to specify the static IP address, Gateway, Subnet Mask, and DNS settings (optional).
IPAddress staticIP(192, 168, 1, 100); // ESP32 static IP
IPAddress gateway(192, 168, 1, 1); // IP Address of your network gateway (router)
IPAddress subnet(255, 255, 255, 0); // Subnet mask
IPAddress primaryDNS(192, 168, 1, 1); // Primary DNS (optional)
IPAddress secondaryDNS(0, 0, 0, 0); // Secondary DNS (optional)Based on the current network settings, select an appropriate static IP address for your ESP32. This address should be within the same subnet as your current network but outside the range your router typically assigns (to avoid IP conflicts).
Once you modify the sketch, upload it to the ESP32.
#include <WiFi.h>
// Replace with your network credentials
const char* ssid = "Your_SSID";
const char* password = "Your_PASSWORD";
// Static IP configuration
IPAddress staticIP(192, 168, 1, 100); // ESP32 static IP
IPAddress gateway(192, 168, 1, 1); // IP Address of your network gateway (router)
IPAddress subnet(255, 255, 255, 0); // Subnet mask
IPAddress primaryDNS(192, 168, 1, 1); // Primary DNS (optional)
IPAddress secondaryDNS(0, 0, 0, 0); // Secondary DNS (optional)
void setup() {
Serial.begin(115200);
// Connect to Wi-Fi
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to WiFi...");
}
// Configuring static IP
if(!WiFi.config(staticIP, gateway, subnet, primaryDNS, secondaryDNS)) {
Serial.println("Failed to configure Static IP");
} else {
Serial.println("Static IP configured!");
}
Serial.print("ESP32 IP Address: ");
Serial.println(WiFi.localIP()); // Print the ESP32 IP address to Serial Monitor
}
void loop() {
// Nothing to do here
}Step 6 � Testing
After uploading the code to your ESP32, use the Serial Monitor to confirm that the ESP32 is now using the static IP address you set.
Static IP vs mDNS
While setting a static IP for your ESP32 is effective, there�s another approach worth considering: mDNS (Multicast DNS). This method offers significant advantages over static IP.
mDNS allows you to access the web server running on your ESP32 using a user-friendly hostname, such as �esp32.local�, rather than fiddling with an IP address. Moreover, even if the IP address of your ESP32 changes, mDNS automatically resolves the new IP address to the same hostname. This means you can keep using the same hostname without worrying about tracking IP address changes.
To learn more about how to implement mDNS on your ESP32, check out our detailed guide here:.
Detailed Code Explanation
The sketch begins by including the WiFi.h library. This library provides the functions needed to connect the ESP32 to a Wi-Fi network and set its IP configuration.
#include <WiFi.h>Next, constants for the Wi-Fi SSID (ssid) and password (password) are defined. You�ll need to replace these with your actual Wi-Fi network�s name and password.
const char* ssid = "Your_SSID";
const char* password = "Your_PASSWORD";Then, IPAddress objects are created for the static IP, gateway, subnet mask, and optionally, primary and secondary DNS servers. These objects will store the respective addresses and are used later to configure the ESP32�s network settings.
// Static IP configuration
IPAddress staticIP(192, 168, 1, 100); // ESP32 static IP
IPAddress gateway(192, 168, 1, 1); // IP Address of your network gateway (router)
IPAddress subnet(255, 255, 255, 0); // Subnet mask
IPAddress primaryDNS(192, 168, 1, 1); // Primary DNS (optional)
IPAddress secondaryDNS(0, 0, 0, 0); // Secondary DNS (optional)Inside the setup() function, serial communication is initiated with the computer.
Serial.begin(115200);The ESP32 attempts to connect to the Wi-Fi network using WiFi.begin(ssid, password). A while loop ensures the ESP32 keeps trying to connect until it succeeds.
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.print(".");
}Once connected to Wi-Fi, the ESP32 is configured to use the previously defined static IP, gateway, subnet mask, and DNS servers using the WiFi.config() function. If there�s an issue configuring the static IP, the message �Failed to configure Static IP� is printed to the Serial Monitor.
if(!WiFi.config(staticIP, gateway, subnet, primaryDNS, secondaryDNS)) {
Serial.println("Failed to configure Static IP");
} else {
Serial.println("Static IP configured!");
}After setting the IP configuration, the ESP32�s current IP address is printed to the Serial Monitor using WiFi.localIP(). If everything goes as planned, this should display the static IP address that was set.
Serial.print("ESP32 IP Address: ");
Serial.println(WiFi.localIP());The IP is set in the setup() function, and since there�s nothing left to do, the loop() function is kept empty.
void loop() {
}