Apache vhosts

Redirecting to another port
YMMV, edit /etc/apache2/sites-available/yoursite.conf

<VirtualHost *:80>
        ServerAdmin hey@whitehouse.gov
        ServerName subdomain.domain.com
        ProxyPass / http://localhost:2368/
        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

then a2ensite subdomain.domain.com or symlink it to sites-enabled.

For the rest:

<VirtualHost *:80>
        ServerName subdomain.domain.com
        DocumentRoot /var/www/html
        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

Caveats: You need to enable the proxy module with a2enmod proxy_http. Also get rid of all default vhost stuff.