PHP: 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

5.0.0 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

}

?>

Example #3 IP validation

ip2long() should not be used as the sole form of IP validation. Combine it with long2ip():


<?php

// make sure IPs are valid. also converts a non-complete IP into

// a proper dotted quad as explained below.

$ip = long2ip(ip2long("127.0.0.1")); // "127.0.0.1"

$ip = long2ip(ip2long("10.0.0")); // "10.0.0.0"

$ip = long2ip(ip2long("10.0.256")); // "10.0.1.0"

?>

Notes

Note: Because PHP's integer type is signed, and many IP addresses will result in negative integers, 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).