Address Allocation Option 1: Manually Configured IP Addresses
Updated: November 10, 2008
Applies To: Windows Server 2008
This option requires technicians or support staff to manually configure IP addresses and related settings, such as subnet masks, default gateways, and DNS suffixes on computers and network devices. In the case of Windows operating systems, this requires editing properties of the network connection. In other operating systems, configuration can involve the creation or modification of configuration files. Depending on the type of device, it might be possible to automate this process. For example, when deploying Windows-based computers, IP address information can be included in unattended information files used during automatic software builds.
In addition to the address configuration task, it is essential to have a clear plan and documentation system in place to ensure that the correct addresses are used and the same addresses are not allocated more than once. Many devices, including Windows-based computers, report a failure and refuse to bind an IP address if an Address Resolution Protocol discovery shows that it is already bound to another device.
The advantages of manually configured IP addresses include:
Simple approach: This option is the simplest approach to understand and is not dependent on any other technology or service. If the correct IP address configuration information is used, the device will have a functional IP stack and will be able to communicate on the network.
Fixed and predictable: Manually configured addresses are fixed and therefore predictable. Allocating addresses from central servers can result in changes to the address or to its associated IP information; if these changes are not anticipated, there can be network problems.
The disadvantages of manually configured IP addresses include:
High overhead: Using manual configuration to maintain all IP addresses across an enterprise network would generate excessive overhead expense. There would also be a great risk of errors and incorrect configurations due to the numbers of addresses that need to be managed. However, this approach is feasible if the network is small or if manual configuration is used only in parts of a larger network.
Risk of wasting addresses: Manually configured addressing can lead to the waste of IP addresses. Devices with an assigned address might be decommissioned but the IP address cannot be reused without some means of reclaiming those no longer in use.
Mobile device reconfiguration: Devices moved from one part of the network to another must be reconfigured for proper network operation. For mobile computing devices, such as laptop computers or PDAs, such reconfiguration becomes time-consuming; it is an impediment to efficient business operations.