Many businesses place a firewall between the Internet and the inside systems.
This is good protection and it just makes good sense. One common firewalling technique is to serverly restrict access through the firewall from the outside but allow a user on the inside to do most anything through the firewall to the outside. When I am at home, I routinely need to move files between home and work. But, because of the firewall, I can ftp from work to home but not the other way around. So far, so good.