Windows Server 2003 Routing and Remote Access Features and Services

Windows Server 2003 builds on the Routing and Remote Access features that were provided by Windows NT 4.0 and Windows 2000. Routing and Remote Access in Windows Server 2003 includes all the features and services from all previous versions of the Windows server products combined.

The following features were provided by Windows NT 4.0:

• RIP version 2 routing protocol for IP

• Open Shortest Path First (OSPF) routing protocol for IP

• Demand-dial routing and routing over on-demand or persistent WAN links, such as analog phone, ISDN, or Point-to-Point Tunneling Protocol (PPTP)

• Internet Control Message Protocol (ICMP) router discovery

• Remote Authentication Dial-In User Service (RADIUS) client

• IP and IPX packet filtering

• PPTP support for router-to-router VPN connections

• Routing and RAS Admin administrative tool and the Routemon command-line utility

Windows 2000 expanded the remote access capabilities of the Windows line by adding support for the following features:

• Multiprotocol Routing and Remote Access Service that can route IP, IPX, and AppleTalk simultaneously

• Internet Group Management Protocol (IGMP) and support for multicast boundaries

• Network Address Translation (NAT), which simplifies small office or home office (SOHO) network connections to the Internet through addressing and name resolution components

• Layer 2 Tunneling Protocol (L2TP) over Internet Protocol Security (IPSec) support for router-to-router VPN connections and remote access

• Demand-dial routing that can route IP and IPX over on-demand or persistent WAN links, such as analog phone lines, ISDN, or over VPN connections that use either PPTP or L2TP over IPSec

• RRAS integration that provides the ability to integrate a firewall with RRAS and NAT functions

Windows Server 2003 continues the evolution of RRAS by adding some new features. The Routing and Remote Access Service for Windows 2000 and Windows Server 2003 features include the following:

• Point-to-Point Protocol over Ethernet (PPPoE) Dial-On-Demand

• Background Intelligent Transfer Service (BITS)

• NAT Transversal using Universal Plug and Play (UPnP)

• Improved administration and management tools that use a Microsoft Management Console (MMC) snap-in or the Netsh command-line tool

Using Point-to-Point Protocol over Ethernet Dial-on-Demand

The PPPoE dial-on-demand feature provides the option to use Point-to-Point Protocol over Ethernet (PPPoE) in a dial-on-demand network connection, which enables the use of PPPoE with the RRAS NAT feature to connect to the Internet. PPPoE enables an RRAS server to connect to the Internet through a common broadband medium, such as a single DSL line, wireless device, or cable modem. All the users over the Ethernet share a common connection.

Detailing the Background Intelligent Transfer Service 1.5

Background Intelligent Transfer Service (BITS) is a background file transfer mechanism and queue manager. File transfers through BITS are "throttled" to minimize the effect on system performance because of bandwidth consumed. File transfer requests are also persistent across network disconnects and workstation reboots until the file transfer is complete. When the transfer is complete, the application that requested the file transfer is notified of the completion. This feature enables low-priority download operations to complete in the background without affecting users' bandwidth.

Version 1.5 of BITS adds down-level client support through redistribution, file upload support, and optional advanced upload features. Background File Upload requires the BITS server application, which is included in Windows Server 2003 and is available for redistribution for Windows 2000-based servers.

Understanding NAT Transversal Using Universal Plug and Play

NAT Transversal technology was designed to enable network applications to detect the presence of a local NAT device. NAT Transversal provides a means for applications to create port mappings on local NAT devices, such as Internet Connection Sharing (ICS) and other Internet gateway devices that support UPnP. The applications can identify the external IP address and automatically configure port mappings to forward packets from the external port of the NAT to the internal port used by the network application. Independent Software Vendors (ISVs) can use this feature to develop applications that create port mappings on UPnP-enabled NAT devices.