CS 130 Lab #6: Internet basics


In this lab we will take a look at some of the things that make the Internet run, "peeking under the hood", so to speak, in order to uncover a few of the details which are normally hidden by software. We will also try a few user-visible application techniques.

The idea behind this lab is to give you some concrete experience with some of these concepts, so that you can better follow the lectures, and to build your intuitions about how the internet works.

IP addresses

As we have discussed, computers on the Internet each have a unique "phone number" or address, called an IP address. This comes in two forms, either with "words" or with numbers, but typically written with several parts separated by dots. For example,

Follow these steps to find out the (numeric) IP address of the computer you are on:

Keep a paper or text file "log" with this information in it for your demo.

FInd at least two other computers you can use (in other Willamette locations, in your dorm or house, or perhaps in your parents house(s). Find out the IP addresses of these computers and jot them down.

Do you see any patterns relating to geographic or organizational relations? (This is an open-ended question: you may not see any patterns based on the specific computers you checked.)

The ping and tracert commands

You can access some useful internet technical tools from the Windows or Mac OS command line.

The ping command allows you to test a connection to another computer, by sending packets to the destination machine repeatedly and measuring how long it takes the packets to come back. Use a command like this:

ping hydra.willamette.edu

Try using this ping command on several different destination computers and compare the results:

Having trouble copying and pasting from the command line? Use your right mouse button and choose "Mark", then select a rectangular area that you want to copy, then hit Enter (the key). Now you should be able to paste the text you copied (into your "log file" for example).

You can use either of the following web sites to check the geographic location of a machine based on its IP address:

AntiOnline IP locator

NetWorld map

Another useful command will give you information about the route that your packets took to get to some destination. Use the command

tracert hydra.willamette.edu

(or traceroute hydra.willamette.edu on a Mac)

Using this tool and some of the same addresses above, answer these questions:

Email issues

Email is one of the oldest and most widely-used internet protocols ... but does it respect modern standards such as Unicode?

Try cutting and pasting Unicode text from the Word documents of the last lab into an email message to yourself. Do the Unicode characters arrive intact? Do you need to make any special changes in settings (some email programs might require you to specify a message format that uses Unicode).

Can you paste in styled text with fonts such as those in the WingDings font from the original Microsoft Word document? Do they "survive" the email process intact? (If possible, see what happens when you use a font that doesn't exist on a destination machine where you read your email: this may take a little experimentation.)

Using a wiki

We have looked several times at the Wikipedia web site during lecture. This "collaborative on-line encyclopedia" uses a technology called Wiki to allow people to edit web pages on the fly (i.e., to edit them as they browse them).

Wiki tutorial

Read the and do tutorial located at the link below, then show during your demo that you can edit a Wiki sandbox page located at the tutorial to include some text of your own.