'Generate Random IP address using PHP

I would like to generate a random IP adress.

phpnumbers


Solution 1:[1]

On 64-bit PHP:

long2ip(rand(0, 4294967295));

Working in 2021 in any supported PHP version (7.4 and 8.0).

Note: since almost any machine is x64 nowadays and the development of 32-bit operating systems is being abandoned, if this is not working you may probably want to download the x64 version of PHP.

Solution 2:[2]

$ip = long2ip(mt_rand());

This way is slightly more readable.

Solution 3:[3]

According to some answeres here, I decided to add an answere to correct some mistakes that was made...

mt_rand(int $min, int $max);

Some samples used this function with a max values of 4294967295. But this function only supports a max value of 2147483647, whats actually the half. Passing a higher number will return false. Using this function whitout passing anything will also only give the half of the needed value. So

long2ip(mt_rand());

would return a max ip of 127.255.255.255

To have the full range you need some like:

long2ip(mt_rand()+mt_rand());

But even in this sample you will maximum get 255.255.255.254. So to have a full range you need a third mt_rand().

The correct way to get the total range in a short hand code is:

$ip = long2ip(mt_rand()+mt_rand()+mt_rand(0,1));

Beware to use + and not *. Because max value * max value would return 255.255.255.255 as expacted but the chance to get a lower ip isn't that good anymore. To keep good chances using * you could do some like:

$ip = long2ip((mt_rand()*mt_rand(1,2))+mt_rand(0,1));

Solution 4:[4]

You could also get a pool of valid IPs from your own webserver logs, if you have any:

cat /var/log/apache2/access_log |cut -d' ' -f1|egrep -v '[a-z]'|sort|uniq > lotsofip.txt

and then in php:

$ips = file('lotsofip.txt');    
echo $ips[array_rand($ips)];

Solution 5:[5]

For IPV6:

<?php

function randomizeFromList(array $list)
{
    if (empty($list)) {
        return null;
    }
    $randomIndex = random_int(0, count($list) - 1);

    return $list[$randomIndex];
}

function generateIpv6(): string
{
    $ipv6String = '';
    //IPV6 Pattern ([0-9a-fA-F]{0,4}:){1,7}[0-9a-fA-F]{0,4}
    $hexSymbols = [
        '0',
        '1',
        '2',
        '3',
        '4',
        '5',
        '6',
        '7',
        '8',
        '9',
        'a',
        'b',
        'c',
        'd',
        'e',
        'f',
        'A',
        'B',
        'C',
        'D',
        'E',
        'F',
    ];

    $randomLength2 = random_int(1, 7);
    for ($i = 0; $i < $randomLength2; ++$i) {
        $ipv6String    .= randomizeFromList($hexSymbols);
        $randomLength1 = random_int(0, 4);
        for ($j = 0; $j < $randomLength1; ++$j) {
            $ipv6String .= randomizeFromList($hexSymbols);
        }
        $ipv6String .= ':';
    }

    $randomLength3 = random_int(0, 4);
    for ($k = 0; $k < $randomLength3; ++$k) {
        $ipv6String .= randomizeFromList($hexSymbols);
    }

    return $ipv6String;
}

echo(generateIpv6());

Solution 6:[6]

$ip = intval(rand()%255).'.'.intval(rand()%255).'.'.intval(rand()%255).'.'.intval(rand()%255);

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 the_nuts
Solution 2 mmeyer2k
Solution 3
Solution 4
Solution 5 medunes
Solution 6 Eugene

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