PortsLock is a filtering firewall for Windows NT/2000/XP and Windows 2003 Server that fully supports user-level security.
PortsLock is an endpoint security solution that allows system administrators to specify network policy rules based on user and group membership. It provides user-level network policy restrictions for Windows workstations and servers. 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 or groups 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.