Date: 21 Jul 2013 04:13:38 +0000 From: "Mark Delany" <n7w@delta.emu.st> To: freebsd-hackers@freebsd.org Subject: Re: bin/176713: [patch] nc(1) closes network socket too soon Message-ID: <20130721041338.2121.qmail@f5-external.bushwire.net> In-Reply-To: <24574.1374375946@server1.tristatelogic.com> References: <CAGwOe2ZEV3o-=Z1A3PgBtChAEhMbqB5fwPx-7emGbTSJ7AyMPA@mail.gmail.com> <24574.1374375946@server1.tristatelogic.com>
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> servers running certain protocols. For example, the rules of the SMTP > protocol... just to name one... require that a client wait until the > server has sent out an initial greeting banner before the client sends > anything to the server. Some SMTP servers are lenient about enforcing > this protocol rule, so in practice it may often not be necessary to wait A while back "fast talkers" as they were called, were a known signature of some spam bots. The guess is that they would just write the whole SMTP transaction in one write() immediately following the connect() and be done with it. A useful optimization when you're blatting out billions of spam. You don't see a big mention of this in search engines, so I don't know how prevalent they are now. Point being that such an option might be useful to avoid triggering any detectors that might still be looking for this. Mark.
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