UNIX: Plumb an interface for promiscuous traffic

This is nifty if you want to "plumb" (the term used in the Solaris world) and interface. This allows you to initialize the data-link portion of a NIC but not any level-3 stuff (like IP). Why would you use this? Simple....you want to hear everything that comes down the wire but you want no detectable presence on the network at all.

Solaris: ifconfig [iface] plumb

Linus: ifconfig [iface] 0.0.0.0