Date: Fri, 6 Sep 2002 12:24:21 -0700 (PDT) From: Jeff Jirsa <jeff@unixconsults.com> To: Linh Pham <lplist@closedsrc.org> Cc: "Marc G. Fournier" <scrappy@hub.org>, <freebsd-questions@FreeBSD.ORG> Subject: Re: Netcraft no longer sees FreeBSD ... ? Message-ID: <20020906121720.R49440-100000@boris.st.hmc.edu> In-Reply-To: <20020906115715.J39314-100000@q.closedsrc.org>
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On Fri, 6 Sep 2002, Linh Pham wrote: > # Does anyone know what Netcraft uses to determine uptime? > > My guess is that it periodically queries your machine once enough > requests have been made. If it gets a host unreachable, connection > refused or something like that... then it will mark that the server as > "down". Yeah... it doesn't make as much sense as using 'uptime' since > sites behind load balancers can really inflate the numbers. No. Netcraft (like many scanning tools) uses characteristics of the tcp responses to determine how long a system has been up. It's far more difficult to forge uptime than the webserver information (check out walmart.com's info for an example of webserver forging). For more information on uptime calculation and system identification in general, read the FAQ: http://uptime.netcraft.com/up/accuracy.html - Jeff -- Jeff Jirsa jeff@unixconsults.com -- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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