CS2 Computational Thinking for Scientists - Lab 07In this lab, we will learn about the fundamentals of networking, particularly the creation and delivery of IP (Internet Protocol) packets.
IP addressAn Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. In the first experiment, you will learn how to get the IP address of your own computer, and the IP address of othe web servers.
Three Ways to Get the IP Address
IP Address and Domain NameAs we have already seen, IP address is a long string of numbers and is not easy to be memorized. Is there any other way to represent each website? The answer is obviously yes, because every time when we open Google, we don't type in the IP address of Google into the browser but simply "www.google.com". For convenience, we use domain name to get the website. Generally, a domain name is an identification string that defines a realm of administrative autonomy, authority or control within the Internet. Domain names are formed by the rules and procedures of the Domain Name System (DNS). Any name registered in the DNS is a domain name like "www.google.com" and "www.cs.ucsb.edu". At the same time, there is a relationship between the IP address and domain name.
In the second experiment, we will learn to get the IP address of the website we want to reach and whether we can connect to that website. We use the Linux command "ping". The usage is:
First we can get the IP address of www.google.com, which is 126.96.36.199. Second, for the ping command, it will send Internet Control Message Protocol (ICMP) Echo Request messages to the destination computer every second (by default) and waiting for a response. The received response means the connection is OK.
RoutingNext, we want to know the route of packet transfer. We use the Linux command "traceroute". In computing, traceroute is a computer network diagnostic tool for displaying the route (path) and measuring transit delays of packets across an Internet Protocol (IP) network. The usage is:
IP packetWe will use a program called Wireshark, which is a free and open-source packet analyzer. It is used for network troubleshooting, analysis, software and communications protocol development,
Download (right click/save as) this file: example.pcapng, and load it into Wireshark. This file is part of packet information transfered on my computer. It contains:
Report: Briefly describe each action you have performed and write the commands, and write (or copy/paste) the results into a file. Submit your report by email.
The lab report (if required) is due 5pm, Friday Mar 6.