PortsLock® is a firewall with user-level access controls for Windows NT/2000/XP. Once PortsLock® is installed, administrators can assign permissions to TCP/IP connections, just as they would in managing permissions on an NTFS partition of a hard disk. It lets you control which users can access what TCP/IP based protocols (HTTP, FTP, SMTP, POP3, Telnet, etc.) on a local computer, depending on the time of day and day of the week. You can also set allowed/denied TCP/UDP ports and IP addresses for incoming and outgoing connections.