Whenever you request a Web page, your browser sends the Web server data about itself. The program http://www.cs.grinnell.edu/~walker/fluency-book/web-info.php displays some of this information.
Click on the above link, scan through the information that it presents, and copy the IP address of the computer you are working on to the clipboard.
Because Internet communication requires an Internet Protocol Number (sometimes called an IP number or an IP address), it is hardly surprising that the server knows this information.
The American Registry for Internet Numbers (ARIN) is a nonprofit organization chartered to manage Internet numbers for North America, a portion of the Caribbean, and sub-equatorial Africa; and ARIN maintains a database of which IP addresses are allocated to whom.
Other groups build upon ARIN's database and other network services to provide further information regarding IP addresses. Two typical sources follow. In each case, try the tool, and describe what information the Web server can locate about your browser and computer.
As we discussed in lecture, messages that are sent over the internet make several "hops" from router to router before reaching their destination. Linux provides a command traceroute that can be used to determine the IP address of each router that the message visits along the way.
For example, the command
$ sudo traceroute -I www.cs.smith.eduwill send an (essentially empty) message to the domain www.cs.smith.edu and then output information about each router that passes the message along. This information usually includes the router's name and IP address; however, the owners of some routers block this information from being reported, in which case the output will include a string of asterisks instead. When that output is included (instead of asterisks), three round-trip times are reported for each of three separate trials, so you can see how long it takes (and what variation the packets might experience).
Open a terminal window and try the traceroute command given above. It should provide a list of routers visited by the query packet, perhaps 20 or so.
It is likely that you will be able to trace most of the geographic path followed by your traceroute message from the domain names of the routers along the path.
For those routers that only give you the IP or do not otherwise indicate their location in the host name, complete the geographic path followed by your traceroute message by searching the ARIN database for the location of organization owning each router in question. (Note that if a sequence of IP addresses along the path begin with the same first three numbers, they belong to the same network, so you really only need to look up one of them.)
If you are interested in tracing the route of packets as they travel to a domain you frequently communicate with, you can do that too. Based on my experience, you may be more successful tracing the path to "small" domains (such as email addresses) than "large" ones (such as hugely successful websites). There are likely to be routers along the way to hugely successful websites that do not allow traceroute to display their IP addresses.
Does the path seem logical? Why or why not?
This lab has highlighted some information transmitted to a Web server from you browser whenever you access a Web page. Also, when cookies are enabled, the Web server can record some data about you for future reference. Of course, if you provide additional information about yourself through a Web form (perhaps when you are making a purchase over the Web), then a Web server will be able to link that personal data with your browser and computer information. The use of that data is left to the discretion of those running the Web server.
Many institutions and companies state their privacy policies regarding any data they collect.
Find and read the privacy policy for one or two websites that you frequent, which you also give information to. Examples could include sites from which you make purchases (perhaps www.amazon.com) and social networking sites (perhaps www.facebook.com).
You might want to consider reading the privacy policy for any Web site before filling out forms on that site.