<?php
$email = 'test@126.c.om';
function testEmail($email)
{
//格式验证
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        return '邮箱格式有误!';
    }
//dns验证
    $mail = explode('@', $email);
    $email = $mail[1];
    if (!checkdnsrr($email,'ANY')) {
        return '无效邮箱！请核对邮箱地址';
    }
    return 'success!';
}
$res = testEmail($email);