From a networking standpoint, Windows NT Server provides the domain security components on top of the existing resource-sharing facilities of Microsoft Windows NT. The domain concept of Microsoft® LAN Manager has been expanded to allow domains to "trust" each other. In addition to the additional network components, fault-tolerance features needed by servers have been included. These features include support for the UPS service, disk mirroring and duplexing, and parity-stripped volumes.
Microsoft Windows NT Server can be added to LAN Manager for OS/2 environments. In a domain situation, the Microsoft Windows NT Server computer must be the primary domain controller. The LAN Manager for OS/2 servers is able to receive security database changes. In addition, the LAN Manager for OS/2 servers will be able to receive file replication from information from the Microsoft Windows NT Server computer. MS-DOS, Windows, Microsoft Windows™ for Workgroups, and LAN Manager for OS/2 workstations continue to use the LAN Manager server for logon services.