Messages in this thread | | | Subject | Re: T/TCP: Syn and RST Cookies | Date | Tue, 21 Apr 1998 00:19:03 -0600 | From | "Eric Schenk" <> |
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Kent Brockman <heathclf@skynet.csn.ul.ie> writes: >Where could I find out more information about the transactions being >played twice?
For the record on this one, the researcher in question is named Mark Smith, and he was, at least a year ago when I last had contact with him, at MIT working with Nancy Lynch. His home page, which contains pointers to some of his work in this area can be found at <http://theory.lcs.mit.edu/~mass/>.
Quick summary for the impatient: T/TCP can get data corruption and replay conditions under certain types of crash conditions (A crash condition means a part of the network hickups. It might be a machine at either end of the link, or it could be a router.) Even stronger, unless all network transactions obey some timing assumptions, no protocol that attempts to do what T/TCP does can work. The open questions as I understand them at this point are: (1) do the given assumptions get violated in realtity often enough that we care? (for example, if the probability is signficicantly lower than the probability of a data corruption that gets past the checksum screen, then we probably don't), and (2) does T/TCP as currently specified even work under the assumption that the timing assumptions in question are obeyed.
Personally, I think T/TCP is a dead issue until these questions are addressed in a complete and serious manner.
-- Eric Schenk www: http://www.loonie.net/~eschenk email: eschenk@loonie.net, eschenk@rogers.wave.ca
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