CertiGuide to A+ (A+ 4 Real)  9  Chapter 14: Networks       9  What is a Network?            9  Troubleshooting Network Problems

Troubleshooting Network Connectivity 1 The Internet

It is possible that the network connectivity troubleshooting steps above do not show a fault. Everything works perfectly using IP addresses, but you still cannot access a resource on the network. The next step is to troubleshoot name resolution.

The manner in which you do this depends on the type of resolution you are attempting. The first step is to use ping with the human friendly resource name you want to access. If you receive a response from ping other than “Unknown Host”, name resolution is not the issue. If ping does reply with “Unknown Host”, the next step is to understand the method you are using for name resolution.

If you are using DNS for name resolution, DNS servers will be configured and they will show up in the output of the IPCONFIG /ALL command. To check name resolution via DNS, use the NSLOOKUP command. Entering NSLOOKUP at a command prompt with no parameters will access its interactive mode. Using this mode has one further advantage; when NSLOOKUP opens its interface it tries to connect to the DNS servers configured on the machine. If the servers are not responsive, NSLOOKUP returns an error that will immediately tell you the problem lies at the server end. However if NSLOOKUP loads successfully, the next step is to attempt some name resolution tests.

If you are using WINS or NetBIOS, name resolution troubleshooting is somewhat harder. Use the NET VIEW command to display a list of resources on the target machine. If this command returns, “System Error 53 has occurred, the network path was not found”, the problem lies with name resolution. If you have a WINS server on the network, ensure it is online and functional. If you are using simple NetBIOS, make sure that any gateways or firewalls between the client machine and the target are not denying NetBIOS data packets.

Troubleshooting Network Connectivity 1 The Internet