jargon.artrocity.com
New Hacker's Dictionary the Jargon File v 4.4.6
A packet sent on a TCP/IP network with a source address of the test loopback interface [127.0.0.1]. This means that it will come back labeled 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?” Compare Christmas tree packet, Godzillagram.