Information Technology Reference
In-Depth Information
IP addresses and operating systems do not directly indicate your
identity, but they do identify the machine you are using. Of course,
the sending of packets along the Internet requires IP addresses for
both the sender and the receiver, so this information can hardly be
kept secret. Also, on the surface, it may seem peculiar that a Web
server would be told details of your operating system and browser,
but this practice has a rational and practical justification. In particu
lar, different browsers on different operating systems may have dif
ferent capabilities and idiosyncrasies. Relatively old browsers may
not be able to interpret new versions of HTML, specific browser ver
sions may not handle PDF files correctly, and so on. For this reason,
some Webpage developers tailor their Web pages to specific envi
ronments. For example, you already read in Chapter 11 that various
developers of browsers may extend HTML standards in differing
ways. Tags specified for standard HTML may work in all browsers,
but expanded tags for Internet Explorer may not work for Netscape.
Thus, if Web developers can detect that you are running Internet
Explorer version 6.0 on Windows 2000 Professional, they may gen
erate only those formatting tags they know will work properly on
your browser, and that might be different than if you were running
Mozilla 1.2b on Macintosh OS X. Also, they may know that a par
ticular browser does not properly handle PDF files based on a stated
application type, and thus they may use an HTML document rather
than the normal PDF document that is sent in response to requests
from other browsers. Thus, the exchange of operating system and
browser information with the server can actually work to your bene
fit and can help tailor Web pages to your browser's capabilities.
To experience directly some of the information routinely trans
mitted to a Web browser, you may wish to view
which is the URL mentioned earlier in this chapter.
when I use the Web?
As already noted, Internet communication requires the IP ad
dresses of both sender and receiver. The Web server and the page
you request therefore will know your machine's IP address during
Internet communication, but not specifically your personal identity.
