SM>> Many sysops, for example, use the .1 address to read mail. It is SM>> quite SM>> expected that sysop want to send a Ping from the address .1, and get a SM>> response to .0.
MvdV> If they use .1 for reading mail, why would they want the answer to go to MvdV> .0?
MvdV> If they want the answer to go to .0, why not send the ping from .0?
I agree. This is a rather stupid example, but I could not invent another quickly. However, it is still much more useful to be able and not to use than not to have and to need.