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PHP: long2ip - Manual
PHP 7.2.23 Release Announcement

long2ip

(PHP 4, PHP 5, PHP 7)

long2ipConverts an long integer address into a string in (IPv4) Internet standard dotted format

Description

long2ip ( int $proper_address ) : string

The function long2ip() generates an Internet address in dotted format (i.e.: aaa.bbb.ccc.ddd) from the long integer representation.

Parameters

proper_address

A proper address representation in long integer.

Return Values

Returns the Internet IP address as a string.

Changelog

Version Description
7.1.0 The parameter type of proper_address has been changed from string to integer.

Notes

Note:

On 32-bit architectures, casting integer representations of IP addresses from string to integer will not give correct results for numbers which exceed PHP_INT_MAX.

See Also

  • ip2long() - Converts a string containing an (IPv4) Internet Protocol dotted address into a long integer
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User Contributed Notes 7 notes

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6
Gabriel Malca
13 years ago
If the function doesn't exist:

<?
    if (!function_exists("long2ip")) {
        function long2ip($long) {
            // Valid range: 0.0.0.0 -> 255.255.255.255
            if ($long < 0 || $long > 4294967295) return false;
            $ip = "";
            for ($i=3;$i>=0;$i--) {
                $ip .= (int)($long / pow(256,$i));
                $long -= (int)($long / pow(256,$i))*pow(256,$i);
                if ($i>0) $ip .= ".";
            }
            return $ip;
        }
    }
?>
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1
klawd at kamundo dot de
7 years ago
Use these two functions to convert from and to numbers compatible to MySQLs INET_ATON and INET_NTOA
<?php
   
function convertIpToString($ip)
    {
       
$long = 4294967295 - ($ip - 1);
        return
long2ip(-$long);
    }
    function
convertIpToLong($ip)
    {
        return
sprintf("%u", ip2long($ip));
    }
?>
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1
Tom Crosley
16 years ago
I wanted to be able to pass an IP address in a URL always as an unsigned int.  I then converted it back as shown below:

$ip_addr = "192.168.100.25";  // example IP address that converts to neg #

$s32int = ip2long($ip_addr);

$us32str = sprintf("%u",$s32int);               // convert to unsigned string

// display orig IP address, signed 32 bit version, unsigned 32 bit ver,
// finally converted back to IP addr

printf("%s ,%d, %s, %s", $ip_addr, $s32int, $us32str,
         long2ip(-(4294967296-$us32str)));

// tested on Linux/Apache PHP 4.1.2
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1
Anonymous
8 years ago
If you're running a 32 bit machine you can get wrong IPs. To prevent from this just cast to float e.g.

<?php
long2Ip32bit
($ip){
   return
long2ip((float)$ip);
}
?>
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0
steve at computurn dot com
11 months ago
For a 32bit safe long2ip, which can accept string or signed integer input, try:

  function safelong2ip($long) {
    $binStr = sprintf("%032s", decbin((float)$long));
    if (strlen($binStr) != 32) {
      throw new Exception("Invalid IPv4 subnet!");
    }

    $ipArr = [];
    for ($i = 0; $i < 4; ++$i) {
      $ipArr[] = bindec(substr($binStr, $i*8, 8));
    }

    return implode('.', $ipArr);
  }
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-3
flobee
14 years ago
when importing ip-ranges to a mysql database using an INT(10) field - NOTE: that you will get problems when using intval() function!

copied from "cleong" : 02-Oct-2001 02:21
intval() handles overflow differently depending on the type of the argument.
<?php
// intval('10000000000') = 2147483647
// intval(1e10) = 1410065408
?>
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-8
php dot net at davidstockton dot com
11 years ago
Beware when processing values that are invalid, you may get values that are different based on the OS.  For instance:

$ip = long2ip(pow(2,32)+1024);

On windows you get 255.255.255.255.  On linux it's 0.0.4.0.

So it seems it would be important to make sure the long you're converting is in the correct range.
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