I tried this site http://anonymizer.cs.cmu.edu:8080/prog/snoop.pl using Mosaic 2.7b2 and was told: Your computer is a X11;Linux 1.2.13 i486. Your Internet browser is NCSA Mosaic. You just visited the Anonymizer Home Page. With Arena it gave me: Your Internet browser is Arena/0.96s libwww/. Lynx came up with even less: Your computer is a Unix box. Your Internet browser is Lynx. I did manage to completely confuse it with:
myriad:~> telnet anonymizer.cs.cmu.edu 8080 Trying 128.2.199.14... Connected to LCON.PC.CS.CMU.EDU. Escape character is '^]'. GET /prog/snoop.pl <HTML><HEAD><!-- blah --> <TITLE>I CAN SEE YOU</TITLE> </HEAD>
<BODY BGCOLOR="78789F" text="#FFFFFF" vlink="#dbdb70" link="#FFFF00" alink="#1010ff" >
<center> <img alt="Anonymizer logo" src="ftp://anonymizer.cs.cmu.edu/pub/I19"> </center>
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Many people surf the web under the illusion that their actions are private and anonymous. Unfortunately, it isn't so. Every time you visit a site, you leave a calling card that reveals where you're coming from, what kind of computer you have, and other details. Most sites keep logs of all your visits. In many cases, this logging may constitute a violation of your privacy.
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Here's a sampling of the kind of information that a site can collect on you (please wait a moment):
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<BLOCKQUOTE><STRONG>
<img src="/let/a.gif"><img src="/let/j.gif"><img src="/let/u.gif"><img src="/let/r.gif"><img src="/let/i.gif"><img src="/let/s.gif"><img src="/let/o.gif"><img src="/let/n.gif"><br>
Your name is probably ajurison, and you can be reached at ajurison@netcom20.netcom.com.
<BR> Your Internet browser is [unknown browser].
This time it actually took a stab at the user name, and got it completely wrong, although the hostname (netcom20.netcom.com) was correct. I suspect it used finger and took a wild guess. The rest of the information is obvious from the User-Agent header, though I find it unusual that the new Mosaic reports the cpu/os type: User-Agent: NCSA_Mosaic/2.7b2 (X11;Linux 1.2.13 i486) libwww/2.12 modified Mosaic 2.4 reports only: User-Agent: NCSA Mosaic for the X Window System/2.4 (L10N-2.4.0) libwww/2.12 modified Lynx reports: User-Agent: Lynx/2.2 libwww/2.14 The statement "Your computer is a Unix box." seems to be just a likely guess, but it could be wrong, because there is a version of lynx for MSDOS. What suprises me is not the information this got, but what it *DIDN'T* get. It never managed to figure out my username, despite the fact that netcom runs identd, and all three web browsers give it my username when they opened the FTP connection. It only reported the hostname in one instance, and seems to be ignoring the info from the ftp session. This "snoop" script isn't getting half the information it could!