Windows NT TCP/IP Network Administration

Appendix C. Microsoft DHCP Option Support

Although the Microsoft DHCP Server supports most of the DHCP options defined by RFC1533 and RFC1541, Microsoft DHCP clients can use only a few of these options. However, if your network includes non-Microsoft DHCP clients, you can configure the Microsoft DHCP Server to provide values for DHCP options that are not supported by Microsoft DHCP clients. Clients that support these DHCP options will use the values provided by the Microsoft DHCP Server. Microsoft DHCP clients will simply ignore values that the server provides for options that they do not recognize.

Table C-1 lists the DHCP options supported by the Microsoft DHCP Server. DHCP options that are also supported by Microsoft clients are bolded. Also, note that options whose values are listed as “a preference-ordered list of IP addresses” have a minimum length of 4 octets (to contain the IP address). If multiple IP addresses are defined for the option, the length must be a multiple of 4 octets. Servers should be listed in the order of preference.

Table C-1. DHCP Options Supported by Microsoft DHCP Server and Microsoft DHCP Clients

#	Name	Description /Value
Basic Options
0	Pad	Single-octet value used to cause subsequent fields to align on word boundaries.
255	End	Single-octet value used to indicate the end of options in the DHCP packet. Following unused octets should be filled with Pad Options.
1	Subnet mask	Four-octet value that specifies the subnet mask of the client subnet per RFC ...