You need to understand that you will create a "virtual" web server to answer multiple ports.
Anyway, let's open the ports.
/etc/apache2/ports.conf
NameVirtualHost *:80NameVirtualHost *:8000Listen 8000
Listen 80
port 80 and port 8000 are opened, but port 8000 will not work even though you may see it as opened.
Create a "virtual" web server to answer port 8000.
Edit following;
/etc/apache2/sites-enabled
You may see a long configuration like...
<VirtualHost *:80>
ServerAdmin webmaster@localhost
DocumentRoot /var/www
<Directory />
Options FollowSymLinks...........................</VirtualHost>
Copy all text, and paste it at the bottom of the file.
And change the second virtual host's port as 8000.
<VirtualHost *:80>
ServerAdmin webmaster@localhost
DocumentRoot /var/www
...........................
</VirtualHost>
< VirtualHost *:8000>
ServerAdmin webmaster@localhost
...........................
</VirtualHost>
That's it.
You can access 2 port after a restart.
sudo service apache2 restart