Checking for private ip ranges...

[StinkFinger]

Hello all,
I am trying to update a function of mine to detect for private ip ranges.
Here is what I have so far, and of course, I am stuck at the part where i
need to compare the $ip to the $private_ip array to see if there is a match.

can anyone help out ? i am searching now on preg_replace, i think that is
where i need to start, but not 100% sure.
Thanks.

function getipaddress()
{
$ip;
if (getenv("HTTP_CLIENT_IP")) $ip = getenv("HTTP_CLIENT_IP");
else if (getenv("REMOTE_ADDR")) $ip = getenv("REMOTE_ADDR");
else if (getenv("HTTP_X_FORWARDED_FOR")) $ip =
getenv("HTTP_X_FORWARDED_FOR");
else $ip = "UNKNOWN";
$private_ip = array("/^0\./", "/^127\.0\.0\.1/", "/^192\.168\..*/",
"/^172\.((1[6-9])|(2[0-9])|(3[0-1]))\..*/", "/^10\..*/", "/^224\..*/",
"/^240\..*/");
//do something here if a match, like die()
return $ip;
}

[StinkFinger]

after some more searching and tinkering, i came up with this:

$private_ip = array("/^0\./", "/^127\.0\.0\.1/", "/^192\.168\..*/",
"/^172\.((1[6-9])|(2[0-9])|(3[0-1]))\..*/", "/^10\..*/", "/^224\..*/",
"/^240\..*/");
while (list ($key, $val) = each ($private_ip)) {
if (preg_match($val, $ip))
{
die("private");
}
}

of course, i won't leave the die() statement there, i'll expand on it later,
now that i know its working.
anyone have any comments or other ideas for this ?