Planning addresses for the corporate network

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

Planning addresses for the corporate network

The following sections describe how IP addresses are assigned for this corporate network scenario.

IP addressing

Network IDs are assigned based on the private network ID of for each network segment that uses a subnet mask of This provides for growth of up to 254 computers on each network segment.

The following table shows the assignment of IP addresses for this scenario.

IP addresses for the corporate network

Segment IP network ID with mask Range of host IDs


Network A,

Network B,

Network C,

Network D,

Network E,

Network F,

Network G,

After planning the network, addresses are assigned (either manually or by using DHCP) in the ranges described in the preceding table for all computers on the backbone and Networks A, B, C, D, E, F, and G.

If more than 254 addresses are needed on a segment, a new segment is configured rather than increasing the network address range. To provide for growth in the network, branch offices are assigned a 254-address range, even if there are not that many computers.

However, if a branch office has 10 to 15 people, the extra addresses in a 254-address range should not be wasted. Instead, variable-length subnets are used to divide the 254 addresses into multiple subnets of different lengths. Both the Routing Information Protocol (RIP) version 2 and the Open Shortest Path First (OSPF) protocols support variable-length subnets.


  • The example companies, organizations, products, people and events depicted herein are fictitious. No association with any real company, organization, product, person or event is intended or should be inferred.

  • Open Shortest Path First (OSPF) is not available on Windows XP 64-bit Edition (Itanium) and the 64-bit versions of the Windows Server 2003 family.