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Re: Lynx and log files

From: Marti <marti47@MEDIAONE.NET>
Date: Sun, 25 Jul 1999 03:31:52 -0400
Message-ID: <000601bed66f$c3e792c0$ea50da18@mcculler2.ne.mediaone.net>
To: "WAI Interest Group Emailing List" <w3c-wai-ig@w3.org>, "Gregory J. Rosmaita" <unagi69@concentric.net>
Although I have not yet succumbed to browser sniffing I do have access to my
server log files and thought you might like a sample of what is recorded.
here are a few of last nights entries:
 "Mozilla/2.0 (compatible; MSIE 3.01; Windows 95)"
"Mozilla/2.0 (compatible; MSIE 3.01; Windows 95)"
"Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt)"
"Mozilla/4.05 [en]C-AtHome0404  (Win95; U)"
"Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt)"
"Mozilla/4.0 (compatible; MSIE 4.01; MSN 2.5; Windows 95)"

If anyone wants to run some tests to see what is recorded from different
browsers you can contact me privately at
-----Original Message-----
From: Gregory J. Rosmaita <unagi69@concentric.net>
To: WAI Interest Group Emailing List <w3c-wai-ig@w3.org>
Date: Sunday, July 25, 1999 2:57 AM
Subject: Re: Lynx and log files

>Len asked:
>>What do the brower sniffer segregators typically do if they encounter a
>>browser they don't recognize
>that's a good question, and one for which i don't have a definitive answer,
>i've never succumbed to the urge to sniff a browser...  i suppose that they
>simply looking for the string (or, rather, prefix) "Mozilla" in the
>header, before issuing an accept, as i doubt that anyone has the energy or
>inclination to maintain a list of excluded browsers and their user-agent
>prefixes...  how diverse the latter are, i don't know -- i don't, for
>know the user-agent header for the w3 browser, and i don't know where to
find a
>definitive list of user-agent headers.. . yet, while i don't know all of
>possible permutations for prefixes are, i do know that MSIE and Netscape
>declare as Mozilla, as does Mosaic, i believe...  don't know about Opera --
>dug around a bit in my C:\browsers\opera directory, but couldn't find
>that contained the user-agent declaration for the browser...
>i searched about a bit in "Connected: An Internet Encyclopedia", in which,
>you look long enough, you can find something about pretty much everything
>technical that has to do with the web, and which is located at
>        http://www.shopthenet.net/publiclibrary/CIE/
>but it is late, and i am tired, so i didn't turn up too terribly much...
>i did find something interesting, though, when i searched MetaCrawler for
>string "browser sniffing":
>        http://msdn.microsoft.com/workshop/management/browser.asp
>which supposedly sniffs not only what browser you are using, but what OS...
>worked with MSIE, as expected, but using Lynx32, it simply returned empty
>values across the board (which i also expected)...    when i tried it using
>Opera 3.51 (i know -- i need to upgrade!), it couldn't tell me the browser
>browser version number (it actually reported "Not Supported"), but it did
>determine that i was running Windows 95...
>i also (courtesy of MetaCrawler) turned up an online course in
>hosted by the University of Nebraska, Lincoln's Instructional Technology
>Group...  they have what appears to be a pretty extensive collection of
>resources located at:
>        http://itg.unl.edu/teaching_resources/
>there, there is an instructional page on browser sniffing, and one using
>fruits of browser sniffing to shunt users either to what it refers to as
>"high-bandwidth" version of the site or the "low-bandwidth" version of the
>site...  the sample source code and accompanying exegesis, clearly shows
>-- at least at the University of Nebraska, Lincoln -- they teach students,
>faculty, and staff to sniff thus:
>1) a javascript runs to check the user-agent header, so as to determine the
>browser, version, and OS
>2) if the javascript detects the prefix "Mozilla" in the user-agent header
>carried by the browser, it assumes that the browser is either Netscape or
>(and if it is not sure, it will assume Netscape, as do the three browser
>sniffing shareware applications that i also stumbled across in the course
of my
>3) if it identifies the browser requesting the document as a "Mozilla"
>compliant browser, it sends the request on to the "high-bandwidth" version
>the site; and, if it fails to find the "Mozilla" prefix, it assumes that
>browser isn't capable of handling graphically oriented content, and shunts
>off either to the low bandwidth version of the site, or to a page that
>the user to join the twentieth century before it ends...
>all of which is a pretty un-discriminating way to discriminate on the basis
>that the check goes no further than the prefix is bourne out by the output
>the browser sniffer that the ITG at UNL uses to demonstrate the javascript
>action... the browser sniffer, located at the following (extremely long)
>when i tried it using Opera, it performed somewhat better than the
>sniffer--while it reported that i was using Netscape (so it does look for
>initial Mozilla!), it also reported my user-agent header as:
>        Mozilla/4.0 (compatible; Opera/3.0; Windows 95) 3.51 [en].
>which i answers the question, "does Opera declare as Mozilla?", with a
>resounding yes...  it also shows that this particular javascript doesn't
>care what follows the "Mozilla" prefix, for if it did, it would have used
>user-agent header to correctly identify the browser...
>so, i suppose that you could declare:
>        Mozilla/4.0 (compatible; Supreme-Ultimate/0.0; DOS 2.0) 0.0 [gd]
>and you could still get around the typical browser sniffer, even though you
>declared a non-existent browser, running on a non-graphical platform, using
>what is probably an un-supported language, as gd is the ISO 639 value for
>actually, i'm not sure how much longer that will be true, however, or even
>it is still true, as i know of a great many sites who indulge in very
>sophisticated browser-sniffing, so as to return to the declared user-agent
>content quote best suited unquote for it...  there are benign uses of it,
>as sniffing browsers by the level of their support for CSS, and then either
>delivering the user to the CSS-enabled version of the site or else the
>(i.e. quote straight HTML unquote) version of the site, but most of the
>i've encountered are more properly classified as mis-uses...
>which is why i would like to see the next iteration of the Web Content
>Accessibility Guidelines address browser sniffing directly, for if a site
>as Triple-A compliant, but only those users using browsers declaring as
>"Mozilla" can breach the browser-sniffer to gain access to that site, then
>site's Triple-A conformance claim is worthless
>i'd be interested in what anyone who has browser sniffed has to say on the
>He that lives on Hope, dies farting
>     -- Benjamin Franklin, Poor Richard's Almanack, 1763
>Gregory J. Rosmaita <oedipus@hicom.net>
>   President, WebMaster, & Minister of Propaganda,
>        VICUG NYC <http://www.hicom.net/~oedipus/vicug/>
Received on Sunday, 25 July 1999 04:09:42 UTC

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