Email verification to know email really exists on server using php - php

Question

i am trying to make a function where i can check if a email really exists or not i searched various forums but the code only works fine with gmail not others i am checking mx records can i do something to connect to those mx records and ask server if email really does exists or not.
I have added much of the code so that you can understand what do i need to do
Thank's
private function verifyEmail($toemail, $fromemail, $getdetails = false)
{
$result='';
$details=' ';
// Get the domain of the email recipient
$email_arr = explode('#', $toemail);
$domain = array_slice($email_arr, -1);
$domain = $domain[0];
// Trim [ and ] from beginning and end of domain string, respectively
$domain = ltrim($domain, '[');
$domain = rtrim($domain, ']');
if ('IPv6:' == substr($domain, 0, strlen('IPv6:'))) {
$domain = substr($domain, strlen('IPv6') + 1);
}
$mxhosts = array();
// Check if the domain has an IP address assigned to it
if (filter_var($domain, FILTER_VALIDATE_IP)) {
$mx_ip = $domain;
} else {
// If no IP assigned, get the MX records for the host name
getmxrr($domain, $mxhosts, $mxweight);
}
if (!empty($mxhosts)) {
$mx_ip = $mxhosts[array_search(min($mxweight), $mxhosts)];
} else {
// If MX records not found, get the A DNS records for the host
if (filter_var($domain, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
$record_a = dns_get_record($domain, DNS_A);
// else get the AAAA IPv6 address record
} elseif (filter_var($domain, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) {
$record_a = dns_get_record($domain, DNS_AAAA);
}
if (!empty($record_a)) {
$mx_ip = $record_a[0]['ip'];
} else {
// Exit the program if no MX records are found for the domain host
$result = 'Invalid Email MX ';
$details .= 'No suitable MX records found.';
return ((true == $getdetails) ? array($result, $details) : $result);
}
}
// Open a socket connection with the hostname, smtp port 25
$connect = #fsockopen($mx_ip, 25);
if ($connect) {
// Initiate the Mail Sending SMTP transaction
if (preg_match('/^220/i', $out = fgets($connect, 1024))) {
// Send the HELO command to the SMTP server
fputs($connect, "HELO $mx_ip\r\n");
$out = fgets($connect, 1024);
$details .= $out."\n";
// Send an SMTP Mail command from the sender's email address
fputs($connect, "MAIL FROM: <$fromemail>\r\n");
$from = fgets($connect, 1024);
$details .= $from."\n";
// Send the SCPT command with the recepient's email address
fputs($connect, "RCPT TO: <$toemail>\r\n");
$to = fgets($connect, 1024);
$details .= $to."\n";
// Close the socket connection with QUIT command to the SMTP server
fputs($connect, 'QUIT');
fclose($connect);
// The expected response is 250 if the email is valid
if (!preg_match('/^250/i', $from) || !preg_match('/^250/i', $to)) {
$result = 'Invalid Email Address';
} else {
$result = 'Valid Email Address';
}
}else{echo 'layht';}
} else {
$result = 'Invalid Email Address';
$details .= 'Could not connect to server';
}
if ($getdetails) {
return array($result, $details);
} else {
return $result;
}
}

Answer 1

The only way to know for certain if an email address exists is to send mail to it and get a response from the user.
In the past, it was possible to query the remote server using SMTP and ask it if the address was valid; however because spammers used this to harvest addresses, it no longer works.
In the past it was also possible to send mail to a server and if it wasn't rejected, assume that it was a valid address, however this is no longer reliable either.