When a DHCP client requests DHCP services, the DHCP server determines which macros match the client. The server processes the macros, using the macro categories to determine the order of processing, from the more general to the specific. The macros are processed in the following order:
Client class macros – the most general category
Network address macros – more specific than Client class
Macros mapped to IP addresses – more specific than Network address
Client ID macros – the most specific category, pertaining to one client
A macro that is included in another macro is processed as part of the containing macro.
If the same option is included in more than one macro, the value set for that option in the macro with the most specific category is used because it is processed last. For example, if a Network address macro contained the lease time option with a value of 24 hours, and a Client ID macro contained the lease time option with a value of 8 hours, the client would receive a lease time of 8 hours.