Learning Objectives

In this lab you will define the functions of TCP/IP port associations and review the common port number assignments. You will also use several utilities that will allow you to explore and analyze protocols, ports, and processes.  When you have completed this lab, you will be able to

•    Define the functions of TCP/IP port associations
•    List some of the well known port number assignments
•    Explore the various protocols, ports, and processes employed in a typical network communication
•    Describe the functions of the DNS advance network services
•    Detail the common client configuration settings of DNS

Lab Materials and Setup

The materials you will need for this lab are
•    Pencil and paper
•    PC running Windows XP, Windows Vista, or Windows 7
•    Internet access


After exploring the higher-layer transport protocols, you would like to know how TCP/IP keeps track of all the different sessions on a typical networked PC. You decide to examine the protocols, ports, and processes involved in the typical browsing of a Web site.

Task 1: Start with a description of the function of a TCP or UDP port.

Task 2: Match the following port numbers to the appropriate protocols.

Port 20    Port 21    Port 22    Port 23    Port 25    Port 69
Port 80    Port no    Port 137    Port 138    Port143    Port 443

Note: Some protocols use more than one port number.

Application    Port

Hint: Windows lists all of the well-known ports and protocol services that are associated with them in a document named “services.” Access this list in Windows 7 by opening Notepad (Start I All Pro­ grams I Accessories I Notepad) and navigating to c:windowssystem32driversetc.  Change the view from “Text Documents (*.txt)” to “All Documents(*.*)” to view and open the services document.

Task 3: The services document is a static list of well-known ports on a Windows PC. You will seldom if ever see all of these endpoint ports open or active at one time. You can view a static listing of the active ports using the netstat command-line utility. netstat has a number of switches to customize the out­ put of the list. Run the netstat   /?command and provide a description of the following switches:

Switch    Description
netstat –a
netstat -b
netstat -n
netstat -o

Note: You’ll be making heavy use of the help functions of commands throughout the rest of the Lab in order to use some of these more advanced functions! When in doubt, type the command and add a space and/? to the end of the command! For example: ping  /?


Having just finished the chapter on network naming in the Mike Meyers’ CompTIA Network+ Guide to Managing and Troubleshooting Networks textbook, you know that you are going to have to implement DNS on the network lab’s systems. You want to get a jump on the setup, so you set out to define DNS and WINS and examine how they are configured on the client machines in use at the home office of ITCF.

Task 1: Describe the function of the DNS service on a TCP/IP network.

Task 2: Local PCs cache any addresses resolved by DNS on the hard disk. To view a display of resolved addresses cached on your PC, you will use the command-line utility ipconfig  /displaydns. Open a command prompt and type ipconfig  /displaydns.  What are your results?


Leave a Reply