Methods and devices for monitoring transactions on a bus are disclosed herein. An embodiment of the device comprises a memory component and a comparator component. The memory component stores at least one address. The comparator component is operatively connected to the memory component and the bus. The comparator component compares an address transmitted over the bus with the stored address for purposes of identifying impermissible addresses. The device causes a transaction associated with an impermissible address to be aborted.