Used to be fun setting up all these port forwardings and access lists using the Cisco PIX and the CLI. I would always hold my breath when I would enter the command, hoping I wouldn't see the four lines of error message. At least the error was obvious from the message. But much more fun and faster than a GUI. Or at least more rewarding. It certainly taught you networking better. All of the inside:outside and outside:inside or whatever the format was taught you public and private, etc.
