Firewalls are often combinations of hardware and software designed to protect a network from outside users.
Different things can happen on different ports.
Most web access is provided on port 80 while most FTP access is provided on port 21. This leaves a large number of other ports available for other uses. In this case all ports are open. When there is no firewall network traffic can flow freely. Note that port 9019 is the default port for TeamWave Workplace.