If you chose to use IIS, Apache or some other external
software as your web server, it most likely has the default HTTP
port 80. So it's very much ok not to include the port number in the
URL. The port of the CF's built-in web server is 8500, which you
obviously don't use if you don't use the built-in web server. Since
the built-in web server isn't meant for production use, it uses a
different port by default so that it doesn't collide with some
other web server you might be running.