zerobounce-mxlookup.php

<?php
function smtp_verify_email($email, $mxhost) {
    $email_arr = explode('@', $email);
    $email_to_basic = preg_replace("/[^A-Za-z0-9]/", '', $email);
    $from_email = "reid+".$email_to_basic."@workmangeneral.co";
    $user = implode('@', array_slice($email_arr, 0, -1));
    $messages = array();
    $valid = "unknown";

    $socket = @fsockopen($mxhost, 25);
    if ($socket) {
        $msg = "HELO $mxhost\r\n";
        fwrite($socket, $msg);
        $messages[] = $msg;
        $messages[] = fgets($socket, 1024);

        $msg = "MAIL FROM:<$from_email>\r\n";
        fwrite($socket, $msg);
        $messages[] = $msg;
        $messages[] = fgets($socket, 1024);

        $msg = "RCPT TO:<$email>\r\n";
        fwrite($socket, $msg);
        $messages[] = $msg;
        $messages[] = fgets($socket, 1024);
      
              $msg = "QUIT\r\n";
        fwrite($socket, $msg);
        $response = fgets($socket, 1024);
        $messages[] = $msg;
        $messages[] = $response;

        fclose($socket);

        if ($response[0] == '2') {
            $valid = "valid";
        } elseif ($response[0] == '5') {
            $valid = "invalid";
        }
    }

    $response = array(
        "email" => $email,
        "mxhost" => $mxhost,
        "messages" => $messages,
        "valid" => $valid
    );

    return json_encode($response);
}

if (!empty($_GET["email"])) {
  $email = $_GET["email"];
  $mxhost = $_GET["mx"];
  header('Content-Type: application/json');
  die(smtp_verify_email($email, $mxhost));
}