Packets that turn up unexpectedly on the wrong networkBecause of Bogus routing entries. Also a packet which has an altogether Bogus (non-registered or ill-formed) {internet address}, such as the test loopBack interface [127.0.0.1]. Such a packet will come Back laBelled with a source address that is clearly not of this earth. "The domain server is getting lots of packets from Mars. Does that gateway have a martian filter?" [Jargon File]