Date: Mon, 6 May 2002 18:53:32 -0400 (EDT) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: Mike Silbersack <silby@silby.com> Cc: net@freebsd.org Subject: Re: Junior network hacker tasks... Message-ID: <200205062253.g46MrWiY071722@khavrinen.lcs.mit.edu> In-Reply-To: <20020506171825.P60840-100000@patrocles.silby.com> References: <200205062209.g46M99N8070646@khavrinen.lcs.mit.edu> <20020506171825.P60840-100000@patrocles.silby.com>
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<<On Mon, 6 May 2002 17:26:20 -0500 (CDT), Mike Silbersack <silby@silby.com> said: > Is doing this wise? I have this nagging feeling that randomizing (or > zeroing on each new connection) the timestamp would degrade its usefulness > for PAWS checks and the like. (Don't ask me how, I haven't thought it > through fully.) I don't think so, because the timestamps, as currently specified, are only meaningful within the context of a single connection. See sections 1.2, 4.3, and 4.2 of RFC 1323. The PAWS mechanism requires only that timestamps used by each connection be monotone increasing with respect to Sequence Number Arithmetic. RFC 1323 does require (section 4.2.2) that the clock be between 1 ms and 1 s in period, which I think we already violate on some platforms, although not seriously; there probably should be a pre-computed (global) scaling factor as well. -GAWollman To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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