auto- +"Ž responder
A program that responds to an e-mail or other inquiry without human intervention. For example, if an e-mail address is no longer valid, an auto-responder in the mail server sends an "undeliverable message" automatically to the sender. If the recipient has a new e-mail address or is on vacation, an auto-responder can be set up to reply with an appropriate message. Many people have received an inordinate amount of auto-responder messages due to e-mail viruses, which send messages to random addresses extracted from the address books of unsuspecting users. If an e-mail address is out-of-date, the auto-responder sends an "undeliverable" message to the sender, who had no idea the message was being sent in the first place.