Chapter 17: Troubleshooting Network Protocols and Services

The Troubleshooting Network Protocols and Services objective domain focuses on the skills you will need to troubleshoot and configure Transmission Control Protocol/ Internet Protocol (TCP/IP) for your users. As a desktop support technician (DST), you will need to know how to troubleshoot connectivity problems that users might have. If a user cannot connect to a resource on a remote server, you should be adept in using such tools as Address Resolution Protocol (ARP), Ping, Ipconfig, Pathping, Nslookup, and the Repair utility to help you discover the reason why. In some cases, it might be a broken connection. In other cases, a user might be able to connect to a host using an IP address but not a host name. You should be able to troubleshoot name resolution problems involving NetBIOS names or host names for which Domain Name System (DNS) or host files are not configured correctly. As a DST, you will not need to configure these name resolution services, but you should be able to answer end-user questions or troubleshoot problems for which name resolution is an issue.

There is no doubt that network security has become a global concern. It is not unusual to see firewalls not only in businesses but in the homes of many nontechnical users. You should be able to support users who have configured Internet Connection Firewall (ICF) on their workstations running Microsoft Windows XP Professional. You should also know how to troubleshoot remote connections that are made to company servers or workstations and know how to connect to remote users’ workstations to offer assistance over the Internet. The use of remote access features can save companies thousands of dollars a year.

Tested Skills and Suggested Practices

The skills that you need to successfully master the Troubleshooting Network Protocols and Services objective domain on the Supporting Users and Troubleshooting a Microsoft Windows XP Operating System exam include the following:

• Troubleshoot TCP/IP. Tools include ARP; the Repair utility; connection properties; and the Ping, Ipconfig, Pathping, and Nslookup commands.

  • Practice 1: From the Run command, practice entering the following commands: ARP –a. Note the IP Address and the MAC (physical/hardware) address displayed. Understand that ARP resolves an IP address to a hardware address. Enter the Ipconfig command, and note the IP address, default gateway, and subnet mask of your workstation. Next enter the Ipconfig command with the /all switch. Note the additional information displayed when Ipconfig /all is entered.

  • Practice 2: Right-click My Network Places, and then right-click Local Area Connection and select Properties. From the Local Area Connections Properties dialog box, double-click Internet Protocol (TCP/IP). Note the available parameters that can be configured in the Internet Protocol (TCP/IP) Properties dialog box. Practice entering an IP address, a subnet mask, and a default gateway address. Be sure you understand the valid range of numbers that can be used in each octet of an IP address, that is, 0–255.

• Troubleshoot name resolution issues.

  • Practice 1: If your workstation is configured with a static IP address, note the DNS server address entered in the Internet Protocol (TCP/IP) Properties dialog box and remove it. Be sure to write it down first. Try to connect to a Web site by using Microsoft Internet Explorer, and observe the error you receive.

  • Practice 2: If you obtain your TCP/IP configuration automatically, use the Ipconfig /all command to obtain the IP address, subnet mask, default gateway, and DNS server IP address information. Select Use The Following IP Address, and enter the information you wrote down from the Ipconfig /all command. Use Internet Explorer to connect to a Web site. Next remove DNS configuration information, and attempt to connect to the same Web site. Does it work? Try a different Web site. Understand what happens when name resolution cannot occur.

• Configure and troubleshoot remote connections.

  • Practice 1: From a command prompt, try to ping a remote workstation or Web site. If your computer is configured with a static IP address, write down the default gateway IP address and then remove it from the properties sheet. Save the new configuration. From a command prompt, attempt to ping the remote Web site that you connected to earlier. Note the error message that you receive when a default gateway address is not available and you attempt to connect to a remote host.

• Configure and troubleshoot Internet Explorer.

  • Practice 1: Right-click Internet Explorer, and select Internet Properties. From the Internet Properties dialog box, observe the options available on the General tab. Change your default Home Page.

  • Practice 2: From the Internet Properties dialog box, select the Security tab. Click on the Trusted Sites icon, and select Sites. Add a site to the list, and then click OK.

• Configure and troubleshoot end-user systems by using remote connectivity tools.

  • Practice 1: From a workstation running Windows XP Professional, right-click My Computer and select Properties. Select the Remote tab, and then select Allow Users To Connect Remotely To This Computer.

  • Practice 2: From a workstation running Windows XP Professional, click Start, and select Help And Support. From the Help And Support Center screen, select Remote Assistance from the Additional Resources heading, and then select Invite Someone To Help You and note the three methods available to send an invitation: Windows Messenger, E-Mail, or Save Invitation As A File (Advanced).