Apache: Note on Using the Server Port Environment Variable in Scripts

The Apache web server is internally connected via port 8080. Therefore, all incoming requests from outside (on port 80 of the public web server IP) are routed to the internal IP and port 8080.

This is important if you read the web server environment variable in your script - in PHP e.g. using $_SERVER['SERVER_PORT'] - and generate a URL. Since the value 8080 is returned here, the URL would not be accessible from outside.