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

Posted by: admin February 25, 2020 Leave a comment

Questions:

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?

How to&Answers:

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:

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;
  }

}
?>

Answer:

I found this little gist
which has simpler/shorter solution than already mentioned here.

Second argument (range) can either be a static ip such as 127.0.0.1 or a range like 127.0.0.0/24.

/**
 * Check if a given ip is in a network
 * @param  string $ip    IP to check in IPV4 format eg. 127.0.0.1
 * @param  string $range IP/CIDR netmask eg. 127.0.0.0/24, also 127.0.0.1 is accepted and /32 assumed
 * @return boolean true if the ip is in this range / false if not.
 */
function ip_in_range( $ip, $range ) {
    if ( strpos( $range, '/' ) == false ) {
        $range .= '/32';
    }
    // $range is in IP/CIDR format eg 127.0.0.1/24
    list( $range, $netmask ) = explode( '/', $range, 2 );
    $range_decimal = ip2long( $range );
    $ip_decimal = ip2long( $ip );
    $wildcard_decimal = pow( 2, ( 32 - $netmask ) ) - 1;
    $netmask_decimal = ~ $wildcard_decimal;
    return ( ( $ip_decimal & $netmask_decimal ) == ( $range_decimal & $netmask_decimal ) );
}

Answer:

if(version_compare($low_ip, $ip) + version_compare($ip, $high_ip) === -2) {
    echo "in range";
}

Answer:

I would always suggest ip2long, but sometimes you need to check networks and etc. I’ve built in the past a IPv4 Networking class, which can be found here on HighOnPHP.

The nice thing about working with IP addressing is it’s flexibility especially when using BITWISE operators. AND’ing, OR’ing and BitShifting will work like a charm.

Answer:

Comparing in range (Including Ipv6 support)

The following two functions were introduced in PHP 5.1.0, inet_pton and inet_pton. Their purpose is to convert human readable IP addresses into their packed in_addr representation. Since the result is not pure binary, we need to use the unpack function in order to apply bitwise operators.

Both functions support IPv6 as well as IPv4. The only difference is how you unpack the address from the results. With IPv6, you will unpack with contents with A16, and with IPv4, you will unpack with A4.

To put the previous in a perspective here is a little sample output to help clarify:

// Our Example IP's
$ip4= "10.22.99.129";
$ip6= "fe80:1:2:3:a:bad:1dea:dad";


// ip2long examples
var_dump( ip2long($ip4) ); // int(169239425)
var_dump( ip2long($ip6) ); // bool(false)


// inet_pton examples
var_dump( inet_pton( $ip4 ) ); // string(4)
var_dump( inet_pton( $ip6 ) ); // string(16)

We demonstrate above that the inet_* family supports both IPv6 and v4. Our next step will be to translate the packed result into an unpacked variable.

// Unpacking and Packing
$_u4 = current( unpack( "A4", inet_pton( $ip4 ) ) );
var_dump( inet_ntop( pack( "A4", $_u4 ) ) ); // string(12) "10.22.99.129"


$_u6 = current( unpack( "A16", inet_pton( $ip6 ) ) );
var_dump( inet_ntop( pack( "A16", $_u6 ) ) ); //string(25) "fe80:1:2:3:a:bad:1dea:dad"

Note : The current function returns the first index of an array. It is equivelant to saying $array[0].

After the unpacking and packing, we can see we achieved the same result as input. This is a simple proof of concept to ensure we are not losing any data.

Finally use,

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

Reference: php.net

Answer:

Btw, in case you need to check multiple ranges at once you can add few rows to the code in order to pass array of ranges. The second argument can be an array or string:

public static function ip_in_range($ip, $range) {
      if (is_array($range)) {
          foreach ($range as $r) {
              return self::ip_in_range($ip, $r);
          }
      } else {
          if ($ip === $range) { // in case you have passed a static IP, not a range
             return TRUE;
          }
      } 
      // The rest of the code follows here..
      // .........
}

Answer:

Here is my approach of the subject.

function validateIP($whitelist, $ip) {

    // e.g ::1
    if($whitelist == $ip) {
        return true;
    }

    // split each part of the IP address and set it to an array
    $validated1 = explode(".", $whitelist);
    $validated2 = explode(".", $ip);

    // check array index to avoid undefined index errors
    if(count($validated1) >= 3 && count($validated2) == 4) {

        // check that each value of the array is identical with our whitelisted IP,
        // except from the last part which doesn't matter
        if($validated1[0] == $validated2[0] && $validated1[1] == $validated2[1] && $validated1[2] == $validated2[2]) {
            return true;
        }   

    }

    return false;
}