So to affect a network connection you need to know the host, the port, and the actions allowed on that port. Most web servers run on port 80. However, in order to avoid conflict with an installed Apache server, our web server will run on port 8080. In order to avoid conflict with other services, it is best to keep HTTP services on port 80 or 8080. These are the two most common. Obviously, if these are used, you must find an open port and alert users to the change.
As with the network client, you should note that these addresses are the common port numbers for the different services. As long as the client asks for the correct service on the right port at the right address, communication will still happen. Google's mail service, for example, did not initially run on the common port numbers but, because they know how to access their accounts, users can still get their mail.
Unlike the network client, all variables in the server are hardwired. Any service that is expected to run constantly should not have the variables of its internal logic set at the command line. The only variation on this would be if, for some reason, you wanted the service to run occasionally and on various port numbers. If this were the case, however, you would still be able to watch the system time and change bindings accordingly.
So our sole import is the socket module.
import socket
Next, we need to declare a few variables.