PHP Manual: Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address

Description

int ip2long ( string $ip_address )

The function ip2long generates an IPv4 Internet network address from its Internet standard format (dotted string) representation.

ip2long will also work with non-complete IP addresses. Read » http://publibn.boulder.ibm.com/doc_link/en_US/a_doc_lib/libs/commtrf2/inet_addr.htm for more info.

Parameters

ip_address: A standard format address.

Return Values

Returns the IPv4 address or FALSE if ip_address is invalid.

Changelog

Version	Description
5.2.10	Prior to this version, ip2long would sometimes return a valid number even if passed an value which was not an (IPv4) Internet Protocol dotted address.
5.0.0	Prior to this version, ip2long returned -1 on failure.

Examples

Example #1 ip2long Example


<?php
$ip = gethostbyname('www.example.com');
$out = "The following URLs are equivalent:<br />\n";
$out .= 'http://www.example.com/, http://' . $ip . '/, and http://' . sprintf("%u", ip2long($ip)) . "/<br />\n";
echo $out;
?>

Example #2 Displaying an IP address

This second example shows how to print a converted address with the printf function in both PHP 4 and PHP 5:


<?php
$ip   = gethostbyname('www.example.com');
$long = ip2long($ip);

if ($long == -1 || $long === FALSE) {
    echo 'Invalid IP, please try again';
} else {
    echo $ip   . "\n";           // 192.0.34.166
    echo $long . "\n";           // -1073732954
    printf("%u\n", ip2long($ip)); // 3221234342
}
?>

Notes

Note:
Because PHP's integer type is signed, and many IP addresses will result in negative integers on 32-bit architectures, you need to use the "%u" formatter of sprintf or printf to get the string representation of the unsigned IP address.

Note:
ip2long will return FALSE for the IP 255.255.255.255 in PHP 5 <= 5.0.2. It was fixed in PHP 5.0.3 where it returns -1 (same as PHP 4).

ip2long