php正则表达式验证ip地址

[php]代码库

$IP = "198.168.1.1";  
if (preg_match('/^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/',$IP)) {  
    echo "Your IP address is ok.";  
} else {  
    echo "Wrong IP address.";  
}