Q. What is a mailer daemon and how did it get that name?

Mailer Daemon is a monthly campus newspaper, published by ISM students.

Mailer Daemon (bounce message)

At the UCB, she performed with the house improv teams Mailer Daemon and fwand.

-- Michael Gerber "The Mailer Daemon from Critical Path."

A mailer daemon installed on an e-mail system can respond to a piece of incorrectly addressed e-mail by generating an automated message to the sender that the message was undeliverable.

On the Internet, you'll most likely encounter it only when your e-mail is not delivered to your recipient -- you'll get back your original message plus an ugly message from a "mailer daemon."

A. Most e-mail users have probably noticed the words "mailer daemon" in the header of an automatic reply or a message that bounced back from an intended recipient's mail server because of a misspelled address or technical problem.

If, for some reason, mailer daemon is unable to deliver an email message you have sent, it will send you a message informing you that the message has not been sent and why it could not be delivered.