What Happens When You Go To a Web Site - What The Server Knows

When you go to a Web site, either by clicking on a hyperlink or by typing in a URL in the location field, your browser (the client program) sends a request to a Web server. This request includes the IP address of your computer system, the URL of the file or Web page you've requested, the time the request was made, and whether the request was successful. If you clicked on a hyperlink from a Web page, the URL of the Web page is also passed to the server. All of this information is kept in log files on the server. It's possible to have the log files analyzed and track all access to a Web server.

The Trail Left On Your Computer

We've seen that each server keeps log files to identify requests for Web pages. So in that sense you leave a trail of your activities on each of the Web servers that you contact. There's also a trail of your activities kept on the computer you use to access the Web. Recently accessed Web pages and a list of the URLs accessed are kept in the cache -- a folder or directory that contains recently viewed Web pages, images, and other resources, and the history list. If you're using a computer to access the Web in a public place, such as a lab or library, then its possible for someone to check on your activities.

Cache

Most Web browsers keep copies of recently accessed Web pages, images, and other files in a folder or directory called the cache. When you return to a Web page you've visited recently, the browser first checks to see if it's available in the cache and retrieves it form your computer rather than retrieving it from a remote site. It's much faster to retrieve a Web page form the cache rather than from a remote site. This is convenient, but it also leaves a record of your activities. It is possible to clear the cache whenever you'd like using the Preferences panel. To do that bring up the Preferences panel by clicking on Edit in the menu bar and select Preferences, next bring up the Cache panel by clicking on Advanced and then click on Cache, and finally clear the disk cache by clicking on Clear Disk Cache.

History List

The Web browser keeps a record of the path you've taken to get to the current location. To see the path and select a site from it, click on Go in the menu bar. The browser also keeps a list of all the Web pages visited recently in the history list. To bring up the history list, press CTRL+H from the keyboard or click on Communicator from the menu bar and select History from that menu. This list is kept around for a time period specified in days. The number of days an item may be kept on the list is set in the Preference panel category titled Navigator. To get to the spot where you can set it, click on Edit in the menu bar, select Preferences, and then click on Navigator. You can also clear the history list from this panel by clicking on Clear History.

Cookies

A cookie is information that's passed to a Web server by the Web browser program. Netscape developed the term and the method for working with cookies. The collection of cookies on a computer is kept file named cookies.txt. A Web server to requests and/or writes a cookie to your computer only if you access a Web page that contains the commands to do that. You have the option to not accept any cookies, to accept cookies that only get returned to the server that put a cookie on your computer, or to be warned before accepting a cookie. To do that click on Edit in the menu bar, select Preferences, and then click on Advanced.

Cookies are sometimes viewed as an invasion of privacy, but they are useful to you in some cases. Suppose you want to visit a site frequently that requires you to give a password or a site that you can customize to match your preferences. When you click on a hyperlink the protocol HTTP is used when you visit a Web site. When a Web page is requested, a connection is made between the client and the server. Once the page is transmitted the connection is terminated. If you visit a site again, the server, through HTTP, has no information about a previous visit. Cookies can be used to keep track of your password or keep track of some preferences you've set for every visit to that site. That way you don't have to enter the information each time you visit.

To get more information about cookies take a look at
the Webopedia entry on cookies
Cookies-Who's watching you and why?