Most SMP/E commands update certain zones. For example, the ACCEPT command updates a distribution zone, and the APPLY command updates a target zone. To specify which zone should be updated by a given command, you must use the SET command. The zone is identified on the BOUNDARY operand, which indicates that all subsequent commands, up to the next SET command, should be processed for the specified zone.

The SET command can also be used to request a particular set of predefined operating options. This is done with the OPTIONS operand. The OPTIONS operand specifies the global zone OPTIONS entry containing the processing options to be used for all subsequent commands, until the next SET command.