Martian
{Packet}s that turn up unexpectedly on the wrong {network}
because 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}]