Many organizations use firewalls or ‘gateways’ to separate their local network from the rest of the outside world. Access is limited, which means WS_FTP or your FTP client needs to be properly configured to work seemlessly with the firewall. A firewall usually requires configuration only one time. Check with the network administrator to retrieve data about the firewall and enter it in WS_FTP’s Firewall dialog screen under Tools. The data you’ll need: Name, Hostname, UserID, Password, Type, Port.

All of this is documented in the WS_FTP Professional Security Guide in Chapter 6, page 29.