Open Mail Relay

An open mail relay is an SMTP server configured in such a way that it allows anyone on the Internet to send e-mail through it, not just mail destined to or originating from known users. This used to be the default configuration in many mail servers; indeed, it was the way the Internet was initially set up, but open mail relays have become unpopular due to their exploitation by spammers and worms. Many relays were closed, or were placed on blacklists by other servers.

Read more about Open Mail Relay:  History and Technology, Abuse By Spammers, Anti-spam Efforts, Modern-day Proponents, Closing Relays

Famous quotes containing the words open and/or mail:

    A temple, you know, was anciently “an open place without a roof,” whose walls served merely to shut out the world and direct the mind toward heaven; but a modern meeting-house shuts out the heavens, while it crowds the world into still closer quarters.
    Henry David Thoreau (1817–1862)

    Always polite, fastidiously dressed in a linen duster and mask, he used to leave behind facetious rhymes signed “Black Bart, Po—8,” in mail and express boxes after he had finished rifling them.
    —For the State of California, U.S. public relief program (1935-1943)