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ACADEMIC COMPUTING and COMMUNICATIONS CENTER | ||||||||
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Cookies on the Web | ||||||
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| What is a Cookie? | ||||||
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An HTTP cookie is a short piece of information (often encoded),
which may be sent to you by the Web server when you visit a Web site. Unless
you've expressly told it not to, your browser will save any cookies it
receives in a file or folder on your hard drive. When you revisit that
site or as you move from page to page within the site, your browser will
automatically to send the cookie back to them.
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| What are cookies good for? | ||||||
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Normally, each visit you make to any Web site is stateless;
the Web server has no way to tell whether you've ever been there before
or what you did when you were there. The two-way exchange of cookies --
the server sends you a cookie, your browser accepts it and sends it back
the next time you visit that site -- provides a convenient way for a Web
server to recognize who you are and keep track of what you're doing.
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| What should you do about cookies? | ||||||
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Automatically rejecting every cookie you're offered is not
a good idea. Bluestem authentication, for example, won't work without cookies.
And cookies can also make things easier for you while you're using a Web
site; for example, most Web "shopping carts" run on them, as do some searches.
But cookies can also be a threat to your privacy. Check out the sample cookies in figure 1 -- my email address is in one of the Netscape cookies, and now they will get it back from me, without my knowing it, each time I visit a Netscape site. But keep in mind that I must have chosen to give my email address to them at some point; your simply accepting a cookie sent by a Web server does not give that server any personal information about you except what you've already told it yourself. (Then again, maybe I didn't; see Active Content on the Web.) I don't think Netscape will abuse this information, but there's nothing to stop them from doing so. I also don't think I'll get into trouble for visiting Netscape from work, but I'm sure there are people working in less open environments who have regretted their visiting certain sites. I use the "accept only cookies that get sent back to the originating server" option (available now only on Netscape 4.0). I also told my browser to "warn me before accepting a cookie." Having to say yes or no to every cookie you're offered can get old pretty fast, but it's not a bad idea to do it for a while so you can see what kinds of cookies you're getting and how often you get them. And don't be afraid to reject a cookie; most Web pages will work just fine without them. Even if they send you one after another after another, as some sites do. Return Contents |
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| How to Set Your Cookie Preferences | ||||||
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Netscape Navigator 3: You can tell Netscape
to notify you each time you're offered a cookie. From the menu bar, select
Options,
then Network Preferences, and click on the Protocols tab.
Netscape Navigator 4: You can choose to accept all cookies, accept only cookies that get sent back to the originating server, or disable cookies altogether, and you can also tell it to ask before accepting cookies. From the menu bar, select Edit, then Preferences…, and click on "Advanced". The cookie options are at the bottom right. Microsoft Internet Explorer 3: You can instruct IE to notify you each time you're offered a cookie. From the menu bar, select View, then Options, and click on the Advanced tab. Microsoft Internet Explorer 4 (and Outlook Express): You have three options: to accept all cookies, ask before accepting cookies, or disable cookies altogether. From the menu bar, select View, then Internet Options, then click on the Advanced tab. Scroll down until you see an icon that is a yellow triangle with an exclamation point in it. Return Contents |
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| For More Information About Cookies | ||||||
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Start at Netscape's "Cookies and Privacy FAQ": http://search.netscape.com/assist/security/faqs/cookies.html
Official specifications for cookies are being worked on by the HTTP Working Group of the Internet Engineering Task Force (IETF); they're on the Web at http://portal.research.bell-labs.com/~dmk/cookie.html Judith Grobe Sachs, judygs@uic.edu |
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| The ADN Connection, April/May/June 1998 | Previous: ADN Free Summer Seminars | Next: Picking Keywords for UIC Search |
| 2002-7-15 connect@uic.edu |
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