Internet Protocol (IP) addresses

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

Internet Protocol (IP) addresses

As outlined in Overview of networking and TCP/IP, using TCP/IP requires that an IP address be provided for each computer. This topic provides a brief description of the options for doing this. For more detailed information, see DHCP and IP Addressing and Routing.

There are two basic approaches for providing an IP address for a server you are installing:

• Dynamic Host Configuration Protocol (DHCP)
  You can provide IP addresses to the computers on your network by configuring one or more DHCP servers, which provide IP addresses dynamically to other computers. A DHCP server must itself be assigned a static IP address. One server or several servers can provide DHCP along with one or more name resolution services, which are called Domain Name System (DNS) and Windows Internet Name Service (WINS). If you want to run Setup before you have finalized your decisions about which server to use as your DHCP server and what static IP address to assign to that server, you can choose Typical settings in the Networking Settings dialog box during Setup and complete the network configuration later. If you do this and there is no DHCP server in the network, Setup will use a limited IP addressing option called Automatic Private IP Addressing (APIPA). During the time that a server is using APIPA, it can communicate only with other computers using APIPA on the same network segment. A server that is using APIPA cannot make connections to the Internet (for browsing or email), and cannot be used with DNS or Active Directory (which depends on DNS). If you know which server you want to use as your DHCP server, when installing that server, in the Networking Settings dialog box in Setup, choose Custom settings, and specify a static IP address and related network settings. For more information, see Specify a static IP address and settings needed for DNS and WINS.

• Static IP addressing
  For certain types of servers, you must assign a static IP address and subnet mask during or after Setup. These servers include DHCP servers, DNS servers, WINS servers, and any server providing access to users on the Internet. It is also recommended that you assign a static IP address and subnet mask for each domain controller. If a computer has more than one network adapter, you must assign a separate IP address for each adapter. If you want to run Setup on a server before you have finalized your decision about the static IP address you want to assign to that server, you can choose Typical settings in the Networking Settings dialog box during Setup and configure that server later. In this situation, if there is a DHCP server in the network, Setup will obtain an IP address configuration from DHCP. If there is no DHCP server in the network, Setup will use Automatic Private IP Addressing (APIPA). APIPA is described in the previous item in this list. For more information about static IP addresses, including private IP addresses (which you choose from certain ranges of addresses) and public IP addresses (which you obtain from an Internet service provider), see IP Addressing and Routing.

After you have formed a plan for IP addressing, the next components to consider are those for name resolution, which is the process of mapping a computer name (something that users can recognize and remember) to the appropriate IP address. For more information, see Name resolution for TCP/IP.