Denial of Service

Denial of service (DoS) attacks are attempts to make a given service impossible or very hard to access. Attacks sometimes use brute force (saturating servers by flooding them with simultaneous queries) or go for a more subtle approach by exhausting a rare resource on the server.

Denial of service attacks often aim to make the Internet in a region paralyzed, or to make some website inaccessible. The former attacks ISP recursive name servers, while the latter target domain authorization server.