mod_perl2 can be easily configured to give you a new Perl interpreter per each session, one which will die when the session expires.

Thus you get the same interpreter for all requests in the same session. A session is identified by an HTTP connection, and it only works if you can use KeepAlive On.

Just store all your filehandles/sockets/and other non-serializable stuff in variables, and use them when you get a request. Same as you would in any command line app.

The fact that the web is 'stateless' does not mean you cannot create stateful things on top of it. It is just more difficult.