A router (200) monitors (302) a data packet sent from an originator (102) via the router and addressed to a destination device (112, 116) other than the router, and determines (304) whether the data packet is potentially harmful to the destination device. The router interrupts (306) transmission of the data packet in response to determining that the data packet is potentially harmful to the destination device, including communicating (307) with a second router to cause the second router to interrupt transmission of a future data packet; and transmits (308) the data packet in response to determining that the data packet is not potentially harmful to the destination device.