Microsoft's Remote Access Server first shipped with LAN Manager 2.1 in 1991. It was included with the Windows NT 3.1 operating system, and has now been significantly enhanced for Windows NT 3.5. RAS features the following capabilities:
The underlying RAS architecture allows clients to run any combination of the network protocols NetBEUI, TCP/IP, or IPX during a RAS session. This means that Windows Sockets and NetWare-aware, as well as NetBIOS applications, can be run remotely. The Point-to-Point Protocol (PPP) is used as the framing mechanism on the wire. Using PPP enables a high degree of interoperability with existing remote access services.
RAS enables Windows NT and the next version of Windows, Windows95, to provide complete services to the Internet. A Windows NT Server 3.5-based computer can be configured as an Internet service provider, offering dial-up Internet connections to a client workstation running Windows NT 3.5 or Windows95. A computer running Windows NT Workstation 3.5 can dial into an Internet-connected computer running Windows NT Server 3.5, or to any one of a variety of industry-standard PPP or SLIP-based Internet servers.
Windows NT 3.5 and RAS fully integrate into a NetWare network. The RAS clients are running IPX and/or NetBIOS, so all applications that typically work when directly connected to the network, continue to work when remotely connected. The RAS server now supports IPX routing, enabling remote clients to gain access to all NetWare resources via the RAS server.
Windows NT Server 3.5 supports up to 256 simultaneous connections. The Windows NT Workstation provides a single RAS connection, primarily for personal use or for very small networks.
Software data compression in RAS allows users to boost their effective throughput. Data is compressed by the RAS client, sent over the wire in a compressed format, and then decompressed by the server. In typical use, RAS software compression doubles effective throughput.
Remote Access Service provides data encryption, in addition to password encryption, to provide privacy for sensitive data. While most RAS users do not need encryption, government agencies, law enforcement organizations, financial institutions, and others benefit from it. Microsoft RAS uses the RC4 encryption algorithm of RSA Data Security Inc.
In April 1994, Microsoft published the 16-bit and 32-bit RAS APIs, which allow corporate developers and solution providers to create custom, remote-enabled applications that can establish a remote connection, use network resources, and re-connect in the event of a communications link failure. Applications developed using these tools will be compatible with Windows95, Windows NT Workstation and Server 3.5, and Windows for Workgroups 3.11.