匹配PHP中的IP地址白名单

Question

I have a list of IP ranges like

$whitelist=array('50*','202.16*','123.168*',');

I want to block all other traffic from seeing the page.

I've tried

 if(in_array($_SERVER['REMOTE_ADDR'],$whitelist)){
    //display page
    }

Answer 1

in_array doesn't use regexs to compare. Also your regex is incorrect the * is a quantifier. That allows zero or more of the previous character.

Try:

$whitelist=array('50\..*','202\.16\..*','123\.168\..*');
if(preg_match('/^(' . implode('|', $whitelist) . ')/', $_SERVER['REMOTE_ADDR'])){

The .* is allowing anything (pretty much(see s modifier http://php.net/manual/en/reference.pcre.pattern.modifiers.php), . is any character and then paired with that quantifier previously mentioned).
The ^ is the start of the string.
\. is a literal ..
The | is an or.

Demo: https://eval.in/571019
Regex Demo: https://regex101.com/r/dC5uI0/1