DHCP options are used to pass TCP/IP configuration information from the DHCP server to the DHCP client. By using DHCP to configure these options, the administrator can centrally control and distribute configurations that would otherwise need to be manually set at the client.
DHCP options are standardized and defined in RFC2132. In Windows 2000, all DHCP options are predefined and available for use. Non-standard options can also be defined on the DHCP server. This should only be done in special cases where a particular software package requires them.
Please note that not all DHCP clients support all standard DHCP options. For example, the Microsoft-based DHCP clients are designed to request only a small subset of the options. The only exception is the Windows 2000 DHCP Client, which can also support the Perform Router Discovery (31) and Static Route (33) options.
Microsoft-based clients request the following options, which are defined as properties of the scope, such as lease duration time:
Renewal Time Option (58)
Rebinding Time Option (59)
IP Address Lease Time Option (51)
Server Identifier Option (54)
Subnet Mask Option (1)
Microsoft-based clients will also request the following options:
Routers Option (3)
Domain Name Option (15)
Domain Name Servers Option (6)
NetBIOS Name Servers Option (44)
NetBIOS Node Type Option (46)
NetBIOS Scope Option (47)
Options in Windows 2000’s DHCP Server can be defined in five different ways: Predefined Options, Server Options, Scope Options, Class Options, ...