Originally Posted by sayhello_to_the_world
port 80 - which is preconfigured.
This is the standard HTTP port, which will need to be open on any production web server. If you want to provide HTTPS access to your site, you will also need to open port 443.
anything else - eg the firewall-port. - that is the port 127.0.0.1
127.0.0.1 isn't a port - it's the loopback IP address, also known as 'localhost'. It's used only for access to services installed on the same server, and is not accessible from elsewhere.
A "firewall port" should not need to be open, as the purpose of a firewall is to control access to other services.
Which other ports need to be open depends on what services need to be accessible across the network. For most web servers, port 80 (and 443) are sufficient, but frequently, port 22 (SSH) will be opened for remote command-line access (though that might be only opened to some other addresses). Some servers, though, might be running other services (for example, chat) which require other ports to be accessible.
You can see what services you have listening by running the following command in a terminal (run as root for info on which programs are using which ports):
netstat -anp -Ainet,inet6 | grep LISTEN
Note that not all of these ports should be openly accessible.