phpBB IP address encoder/decoder

phpBB stores IP addresses in its database but encodes them first.
Sometimes you need to know what's behind this encoded IP.
Here's the tool.


* Note: For the decoding functionality, you can enter multiple encoded IP addresses, one per line.

Talking about IP addresses, here's yours: 54.234.180.187 which encoded looks like 36eab4bb and resolves to ec2-54-234-180-187.compute-1.amazonaws.com

For your reference, here's the source code for this tool.

<html>
    <head>
        <title>phpBB IP address encoder/decoder</title>
        <style type="text/css">
            .result {
                border: solid 1px orange;
                padding: 5px;
                margin: 10px;
            }
            body, td, th {
                font-family: Verdana;
                font-size: 12px;
            }
        </style>
    </head>

    <body>
        <h2>phpBB IP address encoder/decoder </h2>
        phpBB stores IP addresses in its database but encodes them first.
        <br />
        Sometimes you need to know what's behind this encoded IP.
        <br />
        Here's the tool.
        <?php

        /**
         * This function is taken as is from phpBB
         */
        function decode_ip($int_ip)
        {
            $hexipbang = explode('.', chunk_split($int_ip, 2, '.'));
            return hexdec($hexipbang[0]). '.' . hexdec($hexipbang[1]) . '.' . hexdec($hexipbang[2]) . '.' . hexdec($hexipbang[3]);
        }

        /**
         * This function is taken as is from phpBB
         */
        function encode_ip($dotquad_ip)
        {
            $ip_sep = explode('.', $dotquad_ip);
            return sprintf('%02x%02x%02x%02x', $ip_sep[0], $ip_sep[1], $ip_sep[2], $ip_sep[3]);
        }

        $_GET['q'] = trim(@$_GET['q']);

        // check if decoding was requested
        if (!empty($_GET['decode'])) {

            echo '<div class="result">';

            if (empty($_GET['q'])) {
                echo 'No encoded IP entered. Please give me something.';
            } else {

                $input = explode("\n",$_GET['q']);
                echo '<table border="1"><tr><th>Encoded</th><th>Decoded</th><th>Resolved</th></tr>';

                foreach ($input AS $encoded) {
                    $decoded = decode_ip($encoded);
                    echo '<tr><td>' . htmlentities($encoded) . '</td>';
                    echo '<td>' . htmlentities($decoded) . '</td>';
                    echo '<td>' . htmlentities(gethostbyaddr($decoded)) . '</td></tr>';
                }

                echo '</table>';
            }
            echo '</div>';
        }


        // check if encoding
        if (!empty($_GET['encode'])) {

            echo '<div class="result">';

            if (empty($_GET['q'])) {
                echo 'No IP entered. Please give me something.';
            } else {

                $ip_parts = explode('.', $_GET['q']);
                if (count($ip_parts) != 4) {
                    echo 'Malformed IP address given. Give me something like 123.456.789.123, something with three dots in it.';
                } else {
                    echo 'Supplied IP address: ' . htmlentities($_GET['q']);
                    echo '<br />Encoded IP address: ' . htmlentities(encode_ip($_GET['q']));
                }
            }
            echo '</div>';
        }


        // check if resolve
        if (!empty($_GET['resolve'])) {

            echo '<div class="result">';

            if (empty($_GET['q'])) {
                echo 'No IP entered. Please give me something.';
            } else {

                $ip_parts = explode('.', $_GET['q']);
                if (count($ip_parts) != 4) {
                    echo 'Malformed IP address given. Give me something like 123.456.789.123, something with three dots in it.';
                } else {
                    echo 'Supplied IP address: ' . htmlentities($_GET['q']);
                    echo '<br />Resolved IP address: ' . htmlentities(gethostbyaddr($_GET['q']));
                }
            }
            echo '</div>';
        }

        ?>


        <form action="<?php echo htmlentities($_SERVER['PHP_SELF'])?>">

            <textarea name="q" style="width: 280px"><?php echo @htmlentities($_GET['q']); ?></textarea>
            <br />
            <input type="submit" value="Decode IP(s)" name="decode" />
            <input type="submit" value="Encode IP" name="encode" />
            <input type="submit" value="Resolve IP" name="resolve" />
            <br />
        * Note: For the decoding functionality, you can enter multiple encoded IP addresses, one per line.
        </form>

        <?php
            echo '<br />Talking about IP addresses, here\'s yours: <strong>'
                    . htmlentities($_SERVER['REMOTE_ADDR'])
                    . '</strong> which encoded looks like <strong>'
                    . htmlentities(encode_ip($_SERVER['REMOTE_ADDR']))
                    . '</strong> and resolves to <strong>' . htmlentities(gethostbyaddr($_SERVER['REMOTE_ADDR']))
                    . '</strong>';

        ?>
        <hr />
        <p />
        For your reference, here's the source code for this tool.
        <p />
        <?php
            highlight_file($_SERVER['SCRIPT_FILENAME']);
        ?>
    </body>
</html>