用PHP验证邮箱有效性

在sitepoint挖到一篇Verify a User’s Email Address Using PHP，本来打算自己翻译一下，学习一下。所以翻PHP Funtion查找当中出现的函数，无意中就发现checkdnsrr函数那里就有了更精妙的例子，分享给大家！

注意：checkdnsrr函数在win主机上是无效的！！
Verify a User’s Email Address Using PHP中提出了另一种解决办法，写自己的函数：
function myCheckDNSRR($hostName, $recType = '') { if(!empty($hostName)) { if( $recType == '' ) $recType = "MX"; exec("nslookup -type=$recType $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 $line) { if(eregi("^$hostName",$line)) { return true; } } // otherwise there was no mail handler for the domain return false; } return false; }