[PHP] I.P. range authentication

[Will Bown]

I am having trouble verifying if a user is within a specified I.P. range.
The idea is that if a user is at a library within an I.P. range like
231.55.*.* and their I.P. address is 231.55.122.226 a session would be
registered for them. See my code below. This works but only for some I.P.'s
in a range. 

Can anyone suggest a solution or resource that can help me?

$sql = "select  *  from customers where ip1 <=\"$remote_address\" and ip2
>=\"$remote_address\"";
$sql_result = mysql_query($sql,$connection)
 or die("Couldn't execute query. AUTO SIGN IN SELECT");

while ($row = mysql_fetch_array($sql_result)) {
 $ip1 = $row["ip1"];
 $ip2 = $row["ip2"];
   $fname = $row["fname"];
  $lname = $row["lname"];
  $institution = $row["institution"];

$num = mysql_num_rows($sql_result);
$sign_in="$fname $lname $institution";

if($num>0){
 session_register("sign_in");
 }
else{echo" you can't see this page"}

 
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