$_SERVER['REMOTE_ADDR' string and changing subnets - php

Question

I want to expand the IP range that my ~$_SERVER['REMOTE_ADDR'~ check for. The following works and only allows the 10.0.4.* subnet access to the site:
$chk = "10.0.4.";
if( substr($_SERVER['REMOTE_ADDR'],0,strlen($chk)) !== $chk)
$wgGroupPermissions['*']['read'] = false;
When I modify the $chk string to open the site to my entire local network I end up opening the site to the entire world.
$chk = "10.0.";
if( substr($_SERVER['REMOTE_ADDR'],0,strlen($chk)) !== $chk)
$wgGroupPermissions['*']['read'] = false;
I only want my local subnet 10.0.. to have read access to the site. How do I do this?

Answer 1

Using mask is a better way than spliting strings:
function testSubnet($ip, $subnet, $mask) {
$ip = ip2long($ip);
$subnet = ip2long($subnet);
$mask = ip2long($mask);
return ($ip & $mask) == ($subnet & $mask);
}
var_dump(testSubnet('10.0.0.1', '10.0.0.0', '255.255.255.0'));
var_dump(testSubnet('10.0.0.2', '10.0.0.0', '255.255.255.0'));
var_dump(testSubnet('10.0.1.1', '10.0.0.0', '255.255.255.0'));
var_dump(testSubnet('10.0.1.1', '10.0.0.0', '255.255.0.0'));
In this case:
if(testSubnet($_SERVER['REMOTE_ADDR'], '10.0.4.0', '255.255.255.0')) {
// Anything, blablabla...
}

Answer 2

Why can't you just do:
$z = $_SERVER['REMOTE_ADDR'];
function check($ip, $octet = 2) {
$allow = explode(".", "10.0.0.1");
$ipa = explode(".", $ip);
for($i = 0; $i < $octet; $i++) {
$ch .= $ipa[$i];
$ah .= $allow[$i];
}
return $ch == $ah;
}
echo check($z);
Where $octet is the amount of octets you want to match.. The default is 2.

Answer 3

You could use the header() function?
Try this.
$allowed_ip = "10.0.4";
if (!strstr($_SERVER['REMOTE_ADDR'],$allowed_ip))
header("Location: login.php");
// include("login.php");
/* The user will be redirected to another page or you could
always include your login.php page and just continue from there. */