inet_pton

(PHP 5 >= 5.1.0, PHP 7)

inet_pton — Converts a human readable IP address to its packed in_addr representation

Description

string inet_pton ( string $address )

This function converts a human readable IPv4 or IPv6 address (if PHP was built with IPv6 support enabled) into an address family appropriate 32bit or 128bit binary structure.

Parameters

address: A human readable IPv4 or IPv6 address.

Return Values

Returns the in_addr representation of the given address, or FALSE if a syntactically invalid address is given (for example, an IPv4 address without dots or an IPv6 address without colons).

Examples

Example #1 inet_pton() Example


<?php
$in_addr = inet_pton('127.0.0.1');
 
$in6_addr = inet_pton('::1');
?>

Changelog

Version	Description
5.3.0	This function is now available on Windows platforms.

User Contributed Notes

TuRn3r

1 year ago


Be careful, address with leading 0 return false.

Example : 
<?php
inet_pton('172.27.1.04'); // return false
inet_pton('172.27.1.4') ;// return the good result
?>

strata_ranger at hotmail dot com

6 years ago


If the input string is not a readable IP address, inet_pton() generates an E_WARNING and returns FALSE.  The same is true for inet_ntop().

Also, inet_pton() does not recognize netmask notation (e.g: "1.2.3.4/24" or "1:2::3:4/64") in the input string.  This differs from how some database systems (like postgreSQL) support IP address types, so if you need that sort of functionality when processing IP addresses in PHP you'll have to write it in yourself.

A rough example:

<?php

// Sample IP addresses
$ipaddr = '1.2.3.4/24'; // IPv4 with /24 netmask
$ipaddr = '1:2::3:4/64'; // IPv6 with /64 netmask

// Strip out the netmask, if there is one.
$cx = strpos($ipaddr, '/');
if ($cx)
{
  $subnet = (int)(substr($ipaddr, $cx+1));
  $ipaddr = substr($ipaddr, 0, $cx);
}
else $subnet = null; // No netmask present

// Convert address to packed format
$addr = inet_pton($ipaddr);

// Let's display it as hexadecimal format
foreach(str_split($addr) as $char) echo str_pad(dechex(ord($char)), 2, '0', STR_PAD_LEFT);
echo "<br />\n";

// Convert the netmask
if (is_integer($subnet))
{
  // Maximum netmask length = same as packed address
  $len = 8*strlen($addr);
  if ($subnet > $len) $subnet = $len;
  
  // Create a hex expression of the subnet mask
  $mask  = str_repeat('f', $subnet>>2);
  switch($subnet & 3)
  {
  case 3: $mask .= 'e'; break;
  case 2: $mask .= 'c'; break;
  case 1: $mask .= '8'; break;
  }
  $mask = str_pad($mask, $len>>2, '0');

  // Packed representation of netmask
  $mask = pack('H*', $mask);
}

// Display the netmask as hexadecimal
foreach(str_split($mask) as $char) echo str_pad(dechex(ord($char)), 2, '0', STR_PAD_LEFT);

?>

francis dot besset at gmail dot com

4 years ago


It is possible to verify if PHP was compiled with --disable-ipv6 option by AF_INET6 constant.

<?php

if (defined('AF_INET6')) {
  echo "PHP was compiled without --disable-ipv6 option";
} else {
  echo "PHP was compiled with --disable-ipv6 option";
}

?>

me at diogoresende dot net

9 years ago


If you want to use the above function you should test for ':' character before '.'. Meaning, you should check if it's an ipv6 address before checking for ipv4.
Why? IPv6 allows this type of notation:

::127.0.0.1

If you check for '.' character you will think this is an ipv4 address and it will fail.

dave at php dot net