<?php

// Server 1

if(!class_exists("JFactory")){ // no Joomla

    header('Authorization: Bearer 123456789');

} else { // Joomla framework loaded

    $app = JFactory::getApplication();
    $app->setHeader('Authorization: ', 'Bearer 123456789');
    $app->sendHeaders();
}

<?php

// Server 2

$headers = get_headers("http://server1.com/");

foreach($headers as $header) {

        echo $header ."<br/>";

}