How to check if email exists in php?

Question

PHP

Hello everyone, Please tell me how you can check the validity of an email (existence) in php

Answer 1

https://ctrlq.org/code/20152-validate-email-address
Something like this, but in general you should not do this.
Not all servers generally respond correctly.
All this is done for a very long time. a series of different requests to the DNS and the mailer is needed.
Not all servers respond the first time (hello mail.ru, this is such a protection - if you requested 1 email / sent a letter to it once, then you are a spammer and a hacker and you need to give an error, but if you tried to send again, then you are a normal kid) .
In general, the standard mail validation by letter is not just invented.
And the address itself can be checked for validity simply by the mask {asdasd}@{asdasd}.{asdasd}

Answer 2

/*
*  This script was writed by Setec Astronomy - [e-mail]
*
*  This script is distributed under the GPL License
*
*  This program is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
*   GNU General Public License for more details.
*
*  http://www.gnu.org/licenses/gpl.txt
*
*/
define ('DEBUG_OK', true);
class CCheckMail
{
  var $timeout = 10;
  var $domain_rules = array ("aol.com", "bigfoot.com", "brain.net.pk", "breathemail.net",
                "compuserve.com", "dialnet.co.uk", "glocksoft.com", "home.com",
                "msn.com", "rocketmail.com", "uu.net", "yahoo.com", "yahoo.de");

  function _is_valid_email ($email = "")
    { return preg_match('/^[.\w-][email protected]([\w-]+\.)+[a-zA-Z]{2,6}$/', $email); }

  function _check_domain_rules ($domain = "")
    { return in_array (strtolower ($domain), $this->domain_rules); }

  function execute ($email = ""){
    if (!$this->_is_valid_email ($email)) return false;
    $host = substr (strstr ($email, '@'), 1);

    if ($this->_check_domain_rules ($host)) return false;
    $host .= ".";

    if (getmxrr ($host, $mxhosts[0], $mxhosts[1]) == true)  array_multisort ($mxhosts[1], $mxhosts[0]);
    else { $mxhosts[0] = $host;
       $mxhosts[1] = 10;
     }
    if (DEBUG_OK) print_r ($mxhosts);

    $port = 25;
    $localhost = $_SERVER['HTTP_HOST'];
    $sender = '[email protected]' . $localhost;

    $result = false;
    $id = 0;
    while (!$result && $id < count ($mxhosts[0]))
    { if (function_exists ("fsockopen"))
         { if (DEBUG_OK) print_r ($id . " " . $mxhosts[0][$id]);
           if ($connection = fsockopen ($mxhosts[0][$id], $port, $errno, $error, $this->timeout))
          {
              fputs ($connection,"HELO $localhost\r\n"); // 250
              $data = fgets ($connection,1024);
              $response = substr ($data,0,1);
              if (DEBUG_OK) print_r ($data);
              if ($response == '2') // 200, 250 etc.
             {
                fputs ($connection,"MAIL FROM:<$sender>\r\n");
                $data = fgets($connection,1024);
                $response = substr ($data,0,1);
                if (DEBUG_OK) print_r ($data);
                if ($response == '2') // 200, 250 etc.
               {
                  fputs ($connection,"RCPT TO:<$email>\r\n");
                  $data = fgets($connection,1024);
                  $response = substr ($data,0,1);
                  if (DEBUG_OK) print_r ($data);
              if ($response == '2') // 200, 250 etc.
                 {
                    fputs ($connection,"data\r\n");
                    $data = fgets($connection,1024);
                    $response = substr ($data,0,1);
                    if (DEBUG_OK) print_r ($data);
                    if ($response == '2') // 200, 250 etc.
                   { $result = true; }
                     }
               }
             }
          fputs ($connection,"QUIT\r\n");
              fclose ($connection);
              if ($result) return true;
            }
       }
      else  break;
      $id++;
    } //while
    return false;
}
}

$str='[email protected]'
$alter=new CCheckMail();
print "E-mail: ".$str." - ".($alter->execute($str)?'существует':'не существует');