How to check an IP address is within a range of two IPs in PHP?

Question

I have an IP address and I'm given two other IP addresses which together creates an IP range. I want to check if the first IP address is within this range. How can i find that out in PHP?

Answer 1

With ip2long() it's easy to convert your addresses to numbers. After this, you just have to check if the number is in range:

if ($ip <= $high_ip && $low_ip <= $ip) {   echo "in range"; } 

Answer 2

This website offers a great guide and code to do this (which was the first result of a Google search for this question):

<?php  /*  * ip_in_range.php - Function to determine if an IP is located in a  *                   specific range as specified via several alternative  *                   formats.  *  * Network ranges can be specified as:  * 1. Wildcard format:     1.2.3.*  * 2. CIDR format:         1.2.3/24  OR  1.2.3.4/255.255.255.0  * 3. Start-End IP format: 1.2.3.0-1.2.3.255  *  * Return value BOOLEAN : ip_in_range($ip, $range);  *  * Copyright 2008: Paul Gregg <[email protected]>  * 10 January 2008  * Version: 1.2  *  * Source website: http://www.pgregg.com/projects/php/ip_in_range/  * Version 1.2  *  * This software is Donationware - if you feel you have benefited from  * the use of this tool then please consider a donation. The value of  * which is entirely left up to your discretion.  * http://www.pgregg.com/donate/  *  * Please do not remove this header, or source attibution from this file.  */   // decbin32 // In order to simplify working with IP addresses (in binary) and their // netmasks, it is easier to ensure that the binary strings are padded // with zeros out to 32 characters - IP addresses are 32 bit numbers Function decbin32 ($dec) {   return str_pad(decbin($dec), 32, '0', STR_PAD_LEFT); }  // ip_in_range // This function takes 2 arguments, an IP address and a "range" in several // different formats. // Network ranges can be specified as: // 1. Wildcard format:     1.2.3.* // 2. CIDR format:         1.2.3/24  OR  1.2.3.4/255.255.255.0 // 3. Start-End IP format: 1.2.3.0-1.2.3.255 // The function will return true if the supplied IP is within the range. // Note little validation is done on the range inputs - it expects you to // use one of the above 3 formats. Function ip_in_range($ip, $range) {   if (strpos($range, '/') !== false) {     // $range is in IP/NETMASK format     list($range, $netmask) = explode('/', $range, 2);     if (strpos($netmask, '.') !== false) {       // $netmask is a 255.255.0.0 format       $netmask = str_replace('*', '0', $netmask);       $netmask_dec = ip2long($netmask);       return ( (ip2long($ip) & $netmask_dec) == (ip2long($range) & $netmask_dec) );     } else {       // $netmask is a CIDR size block       // fix the range argument       $x = explode('.', $range);       while(count($x)<4) $x[] = '0';       list($a,$b,$c,$d) = $x;       $range = sprintf("%u.%u.%u.%u", empty($a)?'0':$a, empty($b)?'0':$b,empty($c)?'0':$c,empty($d)?'0':$d);       $range_dec = ip2long($range);       $ip_dec = ip2long($ip);        # Strategy 1 - Create the netmask with 'netmask' 1s and then fill it to 32 with 0s       #$netmask_dec = bindec(str_pad('', $netmask, '1') . str_pad('', 32-$netmask, '0'));        # Strategy 2 - Use math to create it       $wildcard_dec = pow(2, (32-$netmask)) - 1;       $netmask_dec = ~ $wildcard_dec;        return (($ip_dec & $netmask_dec) == ($range_dec & $netmask_dec));     }   } else {     // range might be 255.255.*.* or 1.2.3.0-1.2.3.255     if (strpos($range, '*') !==false) { // a.b.*.* format       // Just convert to A-B format by setting * to 0 for A and 255 for B       $lower = str_replace('*', '0', $range);       $upper = str_replace('*', '255', $range);       $range = "$lower-$upper";     }      if (strpos($range, '-')!==false) { // A-B format       list($lower, $upper) = explode('-', $range, 2);       $lower_dec = (float)sprintf("%u",ip2long($lower));       $upper_dec = (float)sprintf("%u",ip2long($upper));       $ip_dec = (float)sprintf("%u",ip2long($ip));       return ( ($ip_dec>=$lower_dec) && ($ip_dec<=$upper_dec) );     }      echo 'Range argument is not in 1.2.3.4/24 or 1.2.3.4/255.255.255.0 format';     return false;   }  } ?>