Your Identity

When You Visit A Website Your Computer Passes Information

Don’t panic – this is normal. No visit to a website is completely anonymous.  Here are some examples of information that may be gleaned from you computer when you visit a website.

Information Pulled by Code on a Web Page –

When you visit a website, the web server hosting the website can collect information about your computer, which is useful for web applications. For example, the following information was generated from your visit using .asp Request.Server.Variables:

<%
response.write(“<b>Name:</b> ” & Request.ServerVariables(“REMOTE_HOST”) & “<br />”)

response.write(“<b>IP:</b> ” & Request.ServerVariables(“REMOTE_ADDR”) & “<br />”)

response.write(“<b>User agent:</b> ” & Request.ServerVariables(“HTTP_USER_AGENT”) & “<br />”)

response.write(“<b>Language:</b> ” & Request.ServerVariables(“HTTP_ACCEPT_LANGUAGE”) & “<br />”)

response.write(“<b>User:</b> ” & Request.ServerVariables(“AUTH_USER”) & “<br />”)

response.write(“<b>Remote:</b> ” & Request.ServerVariables(“REMOTE_USER”) & “<br />”)

response.write(“<b>Server:</b> ” & Request.ServerVariables(“SERVER_NAME”) & “<br />”)
%>

Websites using asp.net can collect additional information. See for example,
http://www.geekpedia.com/tutorial56_Sniffing-visitor-information.html 

Information from Log Files –
In addition the website’s server keeps a log of each request for a page or object on a page. Typically a server log will show:

• Client IP Address
• Request date and time
• Page or object requested
• HTTP code
• bytes served
• User agent (web browser type)
• Referrer (the page that referred you to a website – this tells where you
  came from before you visited a particular page)

Log file analysis software may also be able to tell the website owner the geographic location from which visitors came, how long they stayed, and how frequently they have visited the website or a page on a site.

Open ports on your computer and more — If you would like to find out more about what information can be gleaned from your computer, you may want to visit the ShieldsUP! website. (You will need to click the "proceed" button (if you agree to the terms of the website) and on the subsequent page click on "browser headers" to see what your browser discloses about you.)  ShieldsUP! also has some additional tests
you can run to see whether your computer is vulnerable to exploitation.