990303-4
Discuss the handling of error messages, saying that an e-mail message could not be put into the mailbox of the recipient, in the case where the message was sent via a mailing list.
Answer
Non-delivery notifications, when a message cannot be delivered to a member of a mailing list, can be sent to the list administrator or to the original sender. It is usually best to send them to the list administrator, since he/she can correct errors in the list. But in some cases (usually small, closed lists), it might be better to send them to the original sender, or to both the list administrator and the original sender.
The original sender should, however, get a non-delivery notification if the message could not be delivered to the list expander.
When a list expander distributes a message to list members, it should set the envelope sender (MAIL FROM) to the list moderator, but keep the original sender in the heading of the message. Non-delivery notifications are then returned to the envelope sender, not to the sender specified in the heading of the message.