martian packet
termnetworkingsecurity
A packet whose source or destination address could not legitimately appear where it did, as if it arrived from Mars.
Router requirements (RFC 1812) use the term for addresses that are impossible in context: loopback ranges on the wire, reserved space, or a source that claims to be inside your own network arriving on an outside interface. Linux kernels log them when rp_filter catches spoofed traffic. Martians overlap with bogons but add the directional test: not just 'this prefix should not exist here' but 'this packet could not have come from there'.