What Is TCP/IP?

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

What Is TCP/IP?

In this section

  • Windows Server 2003 TCP/IP

  • TCP/IP Core Protocols

  • TCP/IP Services

  • Related Information

Transmission Control Protocol/Internet Protocol, or TCP/IP, is an industry-standard suite of protocols designed for large internetworks. TCP/IP, which was developed in 1969 by the U.S. Department of Defense (DoD) Advanced Research Projects Agency (DARPA), is the result of a resource-sharing experiment called Advanced Research Projects Agency Network (ARPANET). The TCP/IP protocol was developed to provide high-speed communication network links. Since 1969, ARPANET has grown into a worldwide community of networks known as the Internet.

Before TCP/IP, there was no way for computers to communicate easily and securely on public networks. Windows Server 2003 TCP/IP was designed to make it easy to integrate Microsoft systems into large-scale corporate, government, and public networks, and to provide the ability to operate over those networks in a secure manner. The Windows Server 2003 TCP/IP protocol is installed by default and, unlike previous versions of Windows, cannot be uninstalled. However, you can reset the TCP/IP configuration to a default state with the netsh interface ip reset command.

The Windows TCP/IP suite contains core protocol elements, services, and the interfaces between them. The Transport Driver Interface (TDI) and the Network Device Interface Specification (NDIS) are public, and their specifications are available from Microsoft. In addition, there are a number of higher-level interfaces available to user-mode applications. The most commonly used are Windows Sockets and NetBIOS.

Windows Server 2003 TCP/IP

Windows Server 2003 TCP/IP enables enterprise networking and connectivity. Adding TCP/IP to a Windows Server 2003 configuration offers the following advantages:

  • A standard, routable enterprise networking protocol that is the most complete and accepted protocol available. All modern network operating systems offer TCP/IP support, and most large networks rely on TCP/IP for much of their network traffic.

  • A technology for connecting dissimilar systems. Many standard connectivity utilities are available to access and transfer data between dissimilar systems, including File Transfer Protocol (FTP) and Telnet, a terminal emulation protocol. Several of these standard utilities are included with Windows Server 2003.

  • A robust, scalable, cross-platform client/server framework. Windows Server 2003 TCP/IP offers the Windows Sockets interface, which is ideal for developing client/server applications that can run on Windows Sockets–compliant TCP/IP protocol implementations from other vendors.

  • A method of gaining access to the Internet. The Internet consists of thousands of networks worldwide, connecting research facilities, universities, libraries, private companies, and individuals.


  • The term Internet refers to the worldwide public Internet. An intranet refers to a private IP-based internetwork.

Support for Standard Features

Windows Server 2003 TCP/IP supports the following standard features:

  • Ability to bind to multiple network adapters with different media types.

  • Logical and physical multihoming.

  • Internal IP routing capability.

  • Internet Group Management Protocol (IGMP) (IP multicasting).

  • Duplicate IP address detection.

  • Multiple configurable default gateways.

  • Dead gateway detection.

  • Automatic Path Maximum Transmission Unit (PMTU) discovery.

  • Internet Protocol security (IPSec).

  • Quality of Service (QoS).

  • Asynchronous Transfer Mode Tutorial (ATM) services.

  • Virtual Private Networks (VPNs) with the Point-to-Point Tunneling Protocol (PPTP) and the Layer Two Tunneling Protocol with IPSec (L2TP/IPSec).

Windows Server 2003 TCP/IP Features

The features and improvements of TCP/IP for Windows Server 2003 include the following:

  • Windows Server 2003 and Windows XP (Service Pack 1 or later) now include a production-quality IPv6 protocol stack. For more information about IPv6, see IPv6 Technical Reference.

  • Auto-negotiation of RFC 1323 options (window scaling and TCP timestamps).

  • Default support of network interface cards providing large send offload (LSO) and checksum offload.

  • Internet Group Management Protocol (IGMP) version 3.

  • Reliable multicast with Pragmatic General Multicast (PGM).

  • Alternate configuration of a static IP address configuration.

  • Automatic determination of the interface-related and default route metrics.

TCP/IP Standards

The standards for TCP/IP are published in a series of documents that are called Requests for Comments (RFCs). RFCs describe the internal workings of the Internet. Some RFCs describe network services or protocols and their implementations, whereas others summarize policies. TCP/IP standards are always published as RFCs, although not all RFCs specify standards.

TCP/IP standards are not developed by a committee, but rather by consensus. Anyone can submit a document for publication as an RFC. Documents are reviewed by a technical expert, a task force, or the RFC editor, and then assigned a status. The status specifies whether a document is being considered for becoming a standard.

There are five RFC status assignments, shown below.

RFC Status Assignments

Status Description


Must be implemented on all TCP/IP-based hosts and gateways.


Encouraged that all TCP/IP-based hosts and gateways implement the RFC specifications. Recommended RFCs are usually implemented.


Implementation is optional. Application has been agreed to but is not a requirement.

Limited Use

Not intended for general use.

Not Recommended

Not recommended for implementation.

If a document is being considered for becoming a standard, it goes through stages of development, testing, and acceptance known as the Internet Standards Process. These stages are formally labeled maturity levels. The following table lists the three maturity levels for Internet Standards.

Maturity Levels for Internet Standards

Maturity Level Description

Proposed Standard

This specification is generally stable, has resolved known design issues, is believed to be well understood, has received significant community review, and appears to hold enough community interest to be considered valuable.

Draft Standard

This must be well understood and known to be quite stable, both in its semantics and as a basis for developing an implementation.

Internet Standard

This specification is characterized by a high degree of technical maturity, and it is generally agreed that the specified protocol or service provides significant benefit to the Internet community.

When a document is published, it is assigned an RFC number. If changes are required, a new RFC is published with a new number. The original RFC is never updated. Therefore, it is important to verify that you have the most recent RFC on a particular topic.

RFCs can be obtained in several ways. To obtain any RFC, or a full and current indexed listing of all RFCs published to date, see the IETF RFC Database.

TCP/IP Core Protocols

The TCP/IP protocol component that is installed in your network operating system is a series of interconnected protocols called the TCP/IP core protocols. All other applications and other protocols in the TCP/IP protocol suite rely on the basic services provided by the following protocols: IP, ARP, ICMP, IGMP, TCP, and UDP. For more information about these protocols, see How TCP/IP Works.

TCP/IP Services

The Windows Server 2003 operating system provides the following TCP/IP-related services:

  • Dynamic Host Configuration Protocol (DHCP) client and server and DHCP Relay Agent (with the Routing and Remote Access service).

  • In the absence of a DHCP server, Automatic Private IP Addressing (APIPA) or an alternate static IP address configuration is used.

  • Windows Internet Name Service (WINS), a NetBIOS name client and server.

  • Domain Name System (DNS) client and server, including support for DNS dynamic updates.

  • Dial-up support using the Point-to-Point Protocol (client and server) and Serial Line Internet Protocol (client only).

  • PPTP and L2TP/IPSec, used for remote access and site-to-site VPN connections.

  • TCP/IP network printing (client only with the Lpr.exe and Lpq.exe tools).

  • SNMP agent.

  • NetBIOS interface.

  • Network Location Service.

  • Windows Sockets version 2 (Winsock2) interface.

  • Remote Procedure Call (RPC) support.

  • Network Dynamic Data Exchange (NetDDE).

  • Computer browsing (My Network Places) across IP routers.

  • Reliable multicast with the Pragmatic General Multicast (PGM) protocol.

  • Basic TCP/IP connectivity utilities, including: finger, ftp, rcp, rexec, rsh, telnet, and tftp.

  • Server and client software for simple network protocols, including: Character Generator, Daytime, Discard, Echo, and Quote of the Day.

  • Routing Information Protocol (RIP) listener (for Windows XP Professional) and RIP and Open Shortest Path First (OSPF) (with the Routing and Remote Access service).

  • Network Address Translator (NAT) capabilities using either the Internet Connection Service (ICS) or the NAT/Basic Firewall routing protocol component of the Routing and Remote Access Service.

  • Stateful firewalling capabilities using either the Internet Connection Firewall (ICF) or the NAT/Basic Firewall routing protocol component of the Routing and Remote Access service.

  • Multicast forwarding and IGMP router and proxy capabilities with the Routing and Remote Access Service.

  • TCP/IP management and diagnostic tools, including: arp, ipconfig, nbtstat, netsh, netstat, ping, pathping, route, nslookup, and tracert.

For more information about RFCs, see the IETF RFC Database.