Based on Microsoft Windows Server TechCenter (2010), DHCP servers must be authorized and rightfully configured to a network to provide an effective administrative service. Unintentional damage by unauthorized DHCP servers or servers with wrong configurations to clients is also avoided. Unauthorized DHCP servers, when started, may cause problems such as giving incorrect temporary IP addresses to clients or renewing of current given IP addresses of DHCP clients are wrongly recognized.
Further problems may still arise from these two faults such as clients failing to locate a legitimate domain controller thus preventing clients to log in to a network successfully. DHCP servers may be authorized in Windows depending on its role on the network. For Windows Server 2003, three roles or server types may be considered as a server computer installation: the domain controller, member server and stand-alone server.
When Active Directory is deployed, DHCP servers will be checked if it is domain controller or domain member before authorizing to provide services to clients. To authorize DHCP server in Active Directory: 1. Open DHCP; 2. in the console tree, click DHCP; 3. on the Action menu, click Manage authorized servers. The Manage Authorized Servers dialog box appears; 4. Click Authorize; 5. When prompted, type the name or IP address of the DHCP server to be authorized, and then click OK (Microsoft Corporation 2010).
The valid IP addresses temporarily given to clients on a subnet are called a DHCP scope. These can be configured to establish IPs’ address pool that may be given to clients. There is no limit as to how many scopes can be configured on a DHCP server. Configuring and completion of DHCP scopes on a Microsoft DHCP Server may be done through the use of the DHCP console where a scope wizard is available for use (TopBits 2010).
If in the case that more than one DHCP server is on a subnet, each DCHP server in a multinetted environment must be configured to provide a scope that is within the range of DHCP clients’ subnet use. This scope must then be added to a superscope found on each DHCP server. Note that it is not advisable to have multiple DHCP servers in a network since it may cause a lot of problems when leasing IP addresses to clients (Micorosoft Support 2010). A DHCP reservation is an IP address within a DHCP scope permanently leased to a client instead of a temporary IP address.
It is usually given for computers or devices for printing, file servers or other application servers which are always used and accessed within a network (TopBits 2010). This reservation contains a client’s detailed information. There is some required information for the client: Reservation name. This is given by the client’s administrator; IP address. This will come from the scope or pool consisting of the range of IPs; Client’s MAC (Media Access Control) address. This is recorded without using any hyphens (MWolk. com 2009)