php inside html to detect ip address

php-file.php

<?php
header('Content-Type: text/plain');
echo "Server IP: ".$_SERVER['SERVER_ADDR'];
echo "\nClient IP: ".$_SERVER['REMOTE_ADDR'];
echo "\nX-Forwarded-for: ".$_SERVER['HTTP_X_FORWARDED_FOR'];
?>

php-inside-html.php

      <div class="content_section floating_element">


        <div class="section_header section_header_red">
          <div id="about"></div>
          It works!
        <p>
                <?php
                        echo "Local server IP = ".$_SERVER['SERVER_ADDR'];
                ?>
        </p>
        <p>
                <?php
                        echo "IP used by client = ".$_SERVER['HTTP_HOST'];
                ?>
        </p>
        <p>
                <?php
                        echo "DNS name used by client = ".$_SERVER['SERVER_NAME'];
                ?>
        </p>

test.php

<?php
header('Content-Type: text/plain');
echo "Server IP: ".$_SERVER['SERVER_ADDR'];
echo "\nClient IP: ".$_SERVER['REMOTE_ADDR'];
echo "\nIP used by client = ".$_SERVER['HTTP_HOST'];
echo "\nX-Forwarded-for: ".$_SERVER['HTTP_X_FORWARDED_FOR'];
echo "\nDNS name used by client = ".$_SERVER['SERVER_NAME'];
?>