NTP server

first, get NTP client library for ESP32, and save in Arduino library folder 

https://randomnerdtutorials.com/esp32-ntp-client-date-time-arduino-ide/

Then set time, GMT +5.5 to view Sri Lanka time 

Then upload the code and view serial monitor using Arduino IDE, that should indicate as follows 

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include <WiFi.h>

#include <NTPClient.h>

#include <WiFiUdp.h>

// Replace with your network credentials

const char* ssid     = "Your SSD"; // 

const char* password = "Your Password";

// Define NTP Client to get time

WiFiUDP ntpUDP;

NTPClient timeClient(ntpUDP);

// Variables to save date and time

String formattedDate;

String dayStamp;

String timeStamp;

void setup() {

  // Initialize Serial Monitor

  Serial.begin(115200);

  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());

// Initialize a NTPClient to get time

  timeClient.begin();

  // Set offset time in seconds to adjust for your timezone, for example:

  // GMT +1 = 3600

  // GMT +8 = 28800

  // GMT -1 = -3600

  // GMT 0 = 0

  timeClient.setTimeOffset(19800);

}

void loop() {

  while(!timeClient.update()) {

    timeClient.forceUpdate();

  }

  // The formattedDate comes with the following format:

  // 2018-05-28T16:00:13Z

  // We need to extract date and time

  formattedDate = timeClient.getFormattedDate();

  Serial.println(formattedDate);

  // Extract date

  int splitT = formattedDate.indexOf("T");

  dayStamp = formattedDate.substring(0, splitT);

  Serial.print("DATE: ");

  Serial.println(dayStamp);

  // Extract time

  timeStamp = formattedDate.substring(splitT+1, formattedDate.length()-1);

  Serial.print("HOUR: ");

  Serial.println(timeStamp);

  delay(1000);

}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Unix Time 

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include <TimeLib.h>

unsigned long offset_days = 3;    // 3 days
unsigned long t_unix_date1, t_unix_date2;

void setup() {
  Serial.begin(115200);
  t_unix_date1 = 1564398600;
  Serial.print("t_unix_date1: ");
  Serial.println(t_unix_date1);
  offset_days = offset_days * 86400;    // convert number of days to seconds
  t_unix_date2 = 1564398600 + offset_days;
  Serial.print("t_unix_date2: ");
  Serial.println(t_unix_date2);
  printf("Date1: %4d-%02d-%02d %02d:%02d:%02d\n", year(t_unix_date1), month(t_unix_date1), day(t_unix_date1), hour(t_unix_date1), minute(t_unix_date1), second(t_unix_date1));
  printf("Date2: %4d-%02d-%02d %02d:%02d:%02d\n", year(t_unix_date2), month(t_unix_date2), day(t_unix_date2), hour(t_unix_date2), minute(t_unix_date2), second(t_unix_date2));
}

void loop() {



}