NA Lesson - 15

Troubleshooting TCP/IP Connections

Session Objectives

• IP Config
• Ping
• Network Diagnostics
• Netdiag
• Ping
• Pathping
• Tracert
• ARP

If we have a faulty network connection from a specific host, you can begin by checking your basic IP configuration for errors.

If no errors exist in your IP address, subnet mask, gateway, or other IP configuration parameters, you can use various utilities to determine whether the problem exists at, above, or below the TCP/IP internet layer.

Ipconfig

Use the Ipconfig command to get basic host computer configuration information, including the IP address, subnet mask, and default gateway.

When Ipconfig is used with the /all switch, it produces a more detailed configuration report for all network interfaces.

C:\Ipconfig /all

Network Diagnostics

Network Diagnostics is a graphical troubleshooting tool, built into the Windows Server

2003 interface, that provides detailed information about the local computer’s networking

configuration.

To access the tool, first launch Help And Support from the Start menu. From the Help And Support Center window, click Tools in the Support Tasks area. Finally, expand Help And Support Center Tools from the Tools list, and then select Network Diagnostics.

F1 - Help and Support

Netdiag

Like Network Diagnostics, Netdiag runs a series of tests on the local computer and thendisplays the results of those tests. To troubleshoot network problems, scan the Netdiag output for error messages.

Netdiag is a command-line utility that you must install manually from the Windows Server 2003 installation CD. The utility is included in the group of tools called the Windows Support Tools.

Troubleshooting Using Ping and PathPing

Ping is a tool that helps to verify IP-level connectivity; PathPing is a tool that detects packet loss over multiple-hop trips.

When troubleshooting, the Ping command is used to send an Internet Control Message Protocol (ICMP) echo request to a target host name or IP address Use Ping whenever you want to verify that a host computer can send IP packets to a destination host.

Troubleshooting with Tracert

Tracert is a route-tracing utility that allows you to track the path of a forwarded packet from router to router for up to 30 hops.

Tracert works by sending ICMP echo requests to an IP address, while incrementing the Time to Live (TTL) field in the IP header, starting at 1, and analyzing the ICMP errors that are returned.

Troubleshooting with ARP

• The ARP command is useful for viewing the ARP cache. If two hosts on the same subnet cannot ping each other successfully, try running the ARP command with the –a switch on each computer to see whether the computers have the correct MAC addresses listed for each other. 
• To determine a host’s MAC address, you can use the Ipconfig /all command or the Getmac command. Then use the ARP command with the -d switch to delete any entry that might be incorrect. Add entries by using ARP with the –s switch.

Q. how do you troubleshoot a network configuration using following tools?

            a) IP Config

            b) Network Diagnostics

            c) Netdiag

Q. How do you use the following utilities to troubleshoot faulty connections?

            Ping, pathping, Tracert ARP