In Solaris DHCP, an option is a piece of network information to be passed to a client. The DHCP literature also refers to options as symbols or tags. An option is defined by a numeric code and a text label. An option receives a value when it is used in the DHCP service.
The DHCP protocol defines a large number of standard options for commonly specified network data: Subnet, Router, Broadcast, NIS+dom, Hostname, and LeaseTim are a few examples. A complete list of standard options is shown in the dhcp_inittab man page. You cannot modify the standard option keywords in any way, but you can assign values to the options that are relevant to your network when you include the options in macros.
You can create new options for data that is not represented by the standard options. Options you create must be classified in one of three categories:
Extended – Reserved for options that have become standard DHCP options, but are not yet included in the DHCP server implementation. You might use this if you know of a standard option that you want to use, but do not want to upgrade your DHCP server.
Site – Reserved for options that are unique to your site. The system administrator creates these options.
Vendor – Reserved for options that should apply only to clients of a particular class, such as hardware or vendor platform. The Solaris DHCP implementation includes a number of vendor options for Solaris clients. For example, the option SrootIP4 is used to specify the IP address of a server that a client that boots from the network should use for its root file system.
Chapter 4, Administering DHCP includes procedures for creating, modifying, and deleting options.