Windows NT is not known for its rock-solid security, but that doesn't mean you should leave your servers open for attack. NT includes some security features that can help you control what kind of traffic is able to reach the server.
To configure this information, follow these steps:
By default, the TCP Ports, UDP Ports, and IP Protocols boxes all indicate Permit All, which means that all TCP/IP traffic is accepted.
To only allow certain traffic, choose Permit Only in the appropriate box, and indicate what ports are open on this server. Unfortunately, there isn't a Permit All Except option, which means that an administrator must proactively enable each protocol.
At the top of the TCP/IP Security dialog box, there's an Adapter drop-down list. Choosing the wrong network adapter can severely impact how users handle the resources on the server.