Abstract: A system having replaceable components, each with a MAC address provided by its manufacturer, includes a central system controller which generates predetermined MAC addresses each associated with a slot into which the components are inserted. When a component (card) is inserted into a slot, the controller checks the MAC address of the card and compares it with the MAC address of the slot. If it is not the same (as when a new card is inserted, rather than the same card being re-inserted), the controller instructs the card to store the predetermined MAC address associated with that slot and to use that address as its MAC address. The original MAC address provided by the manufacturer is not deleted but is maintained in a memory location so that it can be accessed when necessary.