http://www.rfc-editor.org/rfc/rfc1948.txt
RFC 1948: Defending Against Sequence Number Attacks, S. Bellovin1996-05-01T23:00:00-00:00IP spoofing attacks based on sequence number spoofing have become a serious threat on the Internet (CERT Advisory CA-95:01). While ubiquitous crypgraphic authentication is the right answer, we propose a simple modification to TCP implementations that should be a very substantial block to the current wave of attacks. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.