<?php
class mail_check_global 
    { 
    var $system_OS             = "win";    // required for MX digging (win / linux) 
    var $debug                 = 0;        // self-explaining (0 - OFF, 1 - ON) 
    var $recType             = "MX";        // limitting dns query to Mail eXchange only 
    var $email;                            // the goal! ;) 
    var $hostName;                        // parent domain for address 
    var $userName;                         // actually NOT used :) 
    var $check_DNS_result;                // debuging DNS check 
    var $check_MAIL_result;                // debuging SYNTAX check 
 
    // check if MX records in DNS server response (WINDOWS !!!): 
    function checkDNS() 
        { 
        if ($this -> system_OS == "linux")         // linuz 
            { 
            if (getmxrr($this -> hostName)) return TRUE; 
                else return FALSE; 
            } else     {                            // windoz 
                    if(!empty($this -> hostName)) 
                        { 
                        exec("nslookup -type=".$this->recType." ".$this -> hostName, $result); 
                       // check each line to find the one that starts with the host 
                       // name. If it exists then the function succeeded. 
                        foreach ($result as $line) 
                            { 
                            if(eregi("^".$this -> hostName,$line)) return true;   
                            } 
                       // otherwise there was no mail handler for the domain 
                       return false; 
                        } 
                     return false; 
                    }         
        } 
 
    // brake address --> username & parent domain 
    function check_email_dns() 
        { 
        list($this -> userName, $this -> hostName) = split("@", $this -> email); 
        if (!$this -> checkDNS ($this -> hostName)) 
            { 
            $this -> check_DNS_result = "Address domain MX DNS record could NOT be found";     
            return FALSE; 
            } else     { 
                    $this -> check_DNS_result = "Address DNS MX is OK";     
                    return TRUE; 
                    } 
        } 
 
    // check addresse's SYNTAX 
    function check_email() 
        { 
        $this -> email = strtolower($this -> email); 
        if (preg_match('/^[-!#$%&'*+./0-9=?A-Z^_`{|}~]+@([-0-9A-Z]+.)+([0-9A-Z]){2,4}$/i', $this -> email)) 
            { 
            $this -> check_MAIL_result = "Address syntax is OK"; 
            return TRUE; 
            } else    { 
                    $this -> check_MAIL_result = "Address syntax is WRONG";     
                    return FALSE;         
                    } 
        } 
 
    // global check 
    function final_mail_check() 
        { 
        if (!$this -> check_email_dns() OR !$this -> check_email()) return FALSE; 
            else return TRUE; 
        } 
 
    // debuging ONLY 
    function debug_address() 
        { 
        if ($this -> debug == 1) 
            { 
            echo "<br>"; 
            echo "<b>DEBUG</b>:"; 
            echo "<br>"; 
            echo "<u>eMail</u>: ".$this -> email; 
            echo "<br>"; 
            echo "<u>DNS</u>: ".$this -> check_DNS_result; 
            echo "<br>"; 
            echo "<u>Syntax</u>: ".$this -> check_MAIL_result ; 
            echo "<br>"; 
            } 
        } 
    } ?>

<?php $check = new mail_check_global;            // initiate class 
$check -> email = "root@yahoo.com";        // REQUIRED --> address to check 
$check -> debug = 1;                    // OPTIONAL --> default is 0; values: 0 / 1 
$check -> system_OS = "win";             // OPTIONAL --> default is WINDOWS; values: win / linux 
 
// USE: if($check -> final_mail_check()) ------------------ your action here --------; 
 
// USE example: 
if ($check -> final_mail_check()) echo "<font style=\"color:green; font-weight:bold\">Email address IS VALID!</font>"; 
    else echo "<font style=\"color:red; font-weight:bold\">The address is NOT VALID!</font>"; 
 
$check -> debug_address();            // debuging purposes 
?>

function check_email($address) { 
    list($local, $host) = explode("@", $address); 
    $pattern_local = "^([0-9a-z]*([-|_]?[0-9a-z]+)*)(([-|_]?)\.([-|_]?)[0-9a-z]*([-|_]?[0-9a-z]+)+)*([-|_]?)$"; 
    $pattern_host  = "^([0-9a-z]+([-]?[0-9a-z]+)*)(([-]?)\.([-]?)[0-9a-z]*([-]?[0-9a-z]+)+)*\.[a-z]{2,4}$"; 
    $match_local = eregi($pattern_local, $local); 
    $match_host = eregi($pattern_host, $host); 
 
    if($match_local && $match_host) { 
        return 1; 
    } else { 
        return 0; 
    } 
}