function validateMail($email){
		   $isValid = true;
		   $atIndex = strrpos($email, '@');
 
		   if(is_bool($atIndex) && !$atIndex){
		      $isValid = false;
		   }else{
		      $domain = substr($email, $atIndex+1);
		      $local = substr($email, 0, $atIndex);
		      $localLen = strlen($local);
		      $domainLen = strlen($domain);
 
		      if ($localLen < 1 || $localLen > 64){
		         $isValid = false;
		      }else if ($domainLen < 1 || $domainLen > 255){
		         $isValid = false;
		      }else if ($local[0] == '.' || $local[$localLen-1] == '.'){
		         $isValid = false;
		      }else if (preg_match('/\\.\\./', $local)){
		         $isValid = false;
		      }else if (!preg_match('/^[A-Za-z0-9\\-\\.]+$/', $domain)){
		         $isValid = false;
		      }else if (preg_match('/\\.\\./', $domain)){
		         $isValid = false;
		      }else if(!preg_match('/^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$/', str_replace("\\\\","",$local))) {
		         if (!preg_match('/^"(\\\\"|[^"])+"$/', str_replace("\\\\","",$local))){
		            $isValid = false;
		         }
		      }
		      if ($isValid && !(checkdnsrr($domain,'MX') || checkdnsrr($domain,'A'))){
		         $isValid = false;
		      }
		   }
 
		   return $isValid;						
		}
// Para implementarlo
if(validateMail('algun@email.com')){
    echo 'email valido';
}else{
    echo 'email no valido';
}