doorstop = D = dot file

DoS attack //

[Usenet,common; note that it's unrelated to `DOS' as name of an operating system] Abbreviation for Denial-Of-Service attack. This abbreviation is most often used of attempts to shut down newsgroups with floods of spam, or to flood network links with large amounts of traffic, or to flood network links with large amounts of traffic, often by abusing network broadcast addresses. Compare slashdot effect.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.