1. A method for providing node security in a router of a packet network, comprising the steps of: monitoring a data packet sent from an originator via the router and addressed to a destination device other than the router; determining in the router whether the data packet is potentially harmful to the destination device; interrupting transmission of the data packet in response to determining that the data packet is potentially harmful to the destination device, comprising the step of communicating with a second router to cause the second router to interrupt transmission of a future data packet; and transmitting the data packet in response to determining that the data packet is not potentially harmful to the destination device.