ping to check for real email addresses

I开发者_开发知识库s there anyway to ping an email address or something such like to check with it is a real working address. I'm not talking about regex or php validate filters etc, but actually checking the address exists??

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It is possible, but not reliable to connect to the recipient mailserver and offer a mail, prompting the mailserver to reject or accept the mail. Not all mail servers will check the validity of adresses, so don't rely on it. Similar question here.

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useful function for check hostname exist(90% worked!):

function validate_email($email)
{
    if(!preg_match ("/^[\w\.-]{1,}\@([\da-zA-Z-]{1,}\.){1,}[\da-zA-Z-]+$/", $email))
        return false;
    list($prefix, $domain) = explode("@",$email);
    if(function_exists("getmxrr") && getmxrr($domain, $mxhosts))
        return true;
    elseif (@fsockopen($domain, 25, $errno, $errstr, 5))
        return true;
    else
        return false;
}

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You could check to see if there are MX records for the corresponding domain: getmxrr() http://php.net/manual/en/function.getmxrr.php

But i would suggest using a two part validation: - first a simple regex for plain validation of input - then a simple check to see if the tld is valid

// pattern was taken from PHP's own source
$pattern =  "/^((\\\"[^\\\"\\f\\n\\r\\t\\b]+\\\")|([A-Za-z0-9_][A-Za-z0-9_\\!\\#\\$\\%\\&\\'\\*\\+\\-\\~\\/\\^\\`\\|\\{\\}]*(\\.[A-Za-z0-9_\\!\\#\\$\\%\\&\\'\\*\\+\\-\\~\\/\\^\\`\\|\\{\\}]*)*))@((\\[(((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9]))\\.((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9]))\\.((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9]))\\.((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9])))\\])|(((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9]))\\.((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9]))\\.((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9]))\\.((25[0-5])|(2[0-4][0-9])|([0-1]?[0-9]?[0-9])))|((([A-Za-z0-9])(([A-Za-z0-9\\-])*([A-Za-z0-9]))?(\\.(?=[A-Za-z0-9\\-]))?)+[A-Za-z]+))$/D";
if (preg_match($pattern, $email)) {
    /**
     * allow ip address as domain OR it should be a valid TLD
     */
    $long = ip2long(substr($email, strrpos($email, '@')+1));
    return (($long !==FALSE && $long>-1)
        || isValidTld(substr($email, strrpos($email, '.')+1)));
}

This is still no garantee that it works but other than sending an email and catching possible bounces ... this is pretty much (aside from the mx-check) it...