Communication on the Internet is based on a group of standards (communications rules) referred to as protocols. The protocols have been developed through the collaboration of business, industry and academia and are published in a set of documents know as RFCs (Request for Comments memorandums). Through the Internet Society, engineers and computer scientists may publish discourse in the form of an RFC, either for peer review or simply to convey new concepts and information.
The Internet Protocol Suite is the set of communications protocols used for the Internet and other similar networks. The Internet Protocol Suite model consists of four layers (RFC 1122). From lowest to highest, these are the Link Layer, the Internet Layer, the Transport Layer, and the Application Layer. Some examples of protocols that are part of the suite are shown below:
You may recognize some of the acronyms that are part of the suite. You've used some new ones in this course like telnet (which Putty uses) and ftp (which WsFTP uses).
When we communicate using the Internet, we use names known as URLs (Uniform Resource Locators, http://forge.emporia.edu) to identify Internet resources. These URLs are translated in IP addresses (see Internet Layer above) which are stored as binary numbers and are usually displayed in human-readable notations, such as 164.113.102.2 (for forge). We can communicate with forge using http://164.113.102.2/, but the URL is easier to remember.
The Internet Protocol uses numerical identifiers for certain types of communications which are known as ports and the identifiers as the port numbers. Some common port numbers used are 80 (HTTP), 23 (telnet) and 21 (ftp). By knowing the ports that are available on a computer attached to the Internet, we can determine (sometimes) what services a particular computer offers.
In this problem you will use a port scanner on your PC as well as on one of the computers in the Math/CS/Econ department. A port scanner is a piece of software designed to search a network host for open ports. This is often used by administrators to check the security of their networks and by hackers to compromise it.
The scanner you will use is called LanPortScan and is available
here. Download the file
LANScan.exe to a directory where you can
find it. Open the directory and just double click on the
icon. The scanner is easy
to set up. You just specify the IP address of the machine to scan and the range
of port numbers to scan.
To find the IP address of your computer, select Start | Run and enter cmd. In the command window enter ipconfig. This will give you basic information on your PC's network card as follows:
For the machine above, the IP address is 192.168.1.100. The results of the scan on this machine for ports 1-200 was:
Your will be scanning two machines over the port range 1-49151:
The PC you use for this course.
forge.emporia.edu (164.113.102.2).
Report a list of all active ports found for both machines. Since the scan involves a large number of ports, you might start the application and go have a large cup of coffee.
What You'll Turn in For This Problem
Use a file compression utility like WinZip and create a file called mp10.zip containing the file mp10.doc. Submit the zipped file to the homework submission system.