(Node.js) MX Lookup Mail Server Domain by Email Address

How to find the mail server for a given email address. Returns the domain name of the primary mail server.

Note: This example requires Chilkat v11.0.0 or greater.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

    var success = false;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var dns = new chilkat.Dns();
    var json = new chilkat.JsonObject();

    var emailAddr = "bob@example.com";

    // This gets all MX domains for an email address.  (Typically one domain.)
    // The preferred domain will be at index 0 (see below).
    success = dns.Query("MX",emailAddr,json);
    if (success == false) {
        console.log(dns.LastErrorText);
        return;
    }

    var i = 0;
    var count_i = json.SizeOfArray("answer.mx");
    while (i < count_i) {
        json.I = i;
        var domain = json.StringOf("answer.mx[i].domain");
        console.log(domain);
        i = i+1;
    }


}

chilkatExample();