What does mask 0.0.0.0 mean when it's assigned to a network interface?

Question

Suppose I use ifconfig or some similar command to setup my network interface, and I assign 0.0.0.0 to the mask parameter. Does it have a special meaning? What implications could this have?

Answer 1

0.0.0.0 generally means that the network interface isn't bound to any network at all, not even localhost requests will be acknowledged. If anything it's a way of the operating system to present the interface as available but inactive and un-routed.