So the encapsulator will not be able to relay the appropriate message to the original sender.

Articles posted to Usenet can be canceled by a special control message (normally from the original sender).

The original sender can have gone offline long before the mail becomes available on the other side.

That way, if the recipient of that message replies to it, the response is routed back to the original sender.

In this way, the file remains available even after the original sender goes offline.

But often e-mail is passed from one machine to another and the identity of the original sender cannot be verified.

The views, opinions, and validity of information expressed are solely the responsibility of the original sender.

That original sender had to pay the 4 cents postage due.

This causes the original sender to regain a new ticket.

If there is no match after two weeks, the computer sends the original sender a rejection note.