Best Practice Ezine #9 – Troubleshooting

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Guy’s Best Practice & Litmus Tests Ezine  #9 � Network Troubleshooting Tips

The theme of this week’s ezine is advice for that moment when the system goes down, and panic or frustration threatens to take over. As well as general strategies, I also have a specific example to troubleshoot network connectivity mysteries.

Contents for Ezine #9

1) Get into a positive frame of mind

Have you ever been on a roll where you solve problems easily? Remember that feeling where nothing can stand in your way? Well hold that thought. If you have ever read any Anthony Robbins, he is a great believer in getting into state. You will be surprised what a difference a ‘can do’ attitude makes to problem solving.

Here are the steps that I use in problem solving.

* Narrow the search. – Ask probing questions.
* Gather information. – Look for clues.
* Develop a theory – What is the most likely cause?
* Test your solution. – Try to alter only one setting at a time.
* Document what you are doing -Only the very best write down the changes they make.
* Narrow the search – Ask questions.

Assuming that your initial flurry of activity failed to come up with an answer, slow down and prepare a check list. Ideally, each question will halve the search area, for example hardware or software.  With 4 or 5 judicious questions, you will soon narrow down the cause of the malfunction.

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Calculating IP Address ranges is a black art, which many network managers solve by creating custom Excel spreadsheets.  IPAT cracks this problem of allocating IP addresses in networks in two ways:

For Mr Organized there is a nifty subnet calculator, you enter the network address and the subnet mask, then IPAT works out the usable addresses and their ranges. 

For Mr Lazy IPAT discovers and then displays the IP addresses of existing computers. Download the Free IP Address Tracker

2) Guy’s Problem Solving List

1) Does the problem stem from Hardware or Software?
2) Should we start with the client end or at the server?
3) Is it the Windows Operating System itself or is it an application like Exchange or SQL?
4) What is the scope of the problem?  One user or many workstations?
5) Which settings have changed? Have any programs been installed or uninstalled?
6) When did the problem start? Once you determine when it began, ask again – what changed just before you noticed the problem?
Note: Never concern yourself with the question ‘Who did it’. No-one ever owns up! Your time is better spent looking for answers.

3) Specific advice for network connectivity problems

Let us take a common network failure and examine the techniques to solve the problem. The situation is that you cannot print or copy files from the client XP workstation to the Windows 2003 server.

Our first question is: Is this hardware or software. The second question should be: What is the scope of the problem, one machine or several? Let us suppose that in this example we have a software problem on one machine.

Now it’s time to try ping, first the local gateway, then the server. Ping works, but you still cannot connect to the server. (If it failed we could also try TraceRT.) Next we try ‘Net use’ and Run, \\ server, neither command yields any useful information. At his point we could ask the supplementary questions. What has changed, and did it ever work!

Diagnosis: In situations where ping gives a response but you still cannot see the server, strongly indicates a problem with DNS. It is worth running IPCONFIG /all, but the place to change the configurations is at the TCP/IP properties (Access though the Network Icon)

What to check: Default Gateway / DNS settings
What to change: If Manual IP -switch to Auto.
If auto IP (DHCP) – Try manual configuration.
Make sure that you add the IP address of at least one DNS server

When you are at the client and you change the IP address of the DNS configuration, try IPCONFIG /registerdns; this saves a reboot. Check your handiwork with IPCONFIG /all.

Connectivity tool kit
Ipconfig /all also /registerdns
Ping and PathPing
Tracert
NSLookup
On the server NETDIAG or DCDIAG

4) General advice on gathering more information

When a problem strikes, make the event logs one of the first places to check. Set the filter to display just the red error messages. Be sure to sift through all 6 logs on a domain controller: System, Application, Security, DNS, Active Directory, File Replication Service.

Use the internet. These days I search Google ahead of searching TechNet. Ask a question in a forum e.g. tek-tips.com. Just the act of formulating your question will help to organize your thoughts, and could produce the answer. Registering the question in the forum will open up the problem to thousands of techies; a new friend in a different time zone may have seen your problem before and have at least a partial answer.

While you are waiting for a reply from the forum, investigate Windows 2000 and XP’s built-in help. In particular try Help, Troubleshooters and check if you have missed anything obvious.

Finally, once you have succeeded, if you write down how you solved the problem, I guarantee that the problem will never reoccur. O.K, even if I am wrong, you will have the answer ready! So make a folder for solved problems; save URL’s of handy sites such as tek-tips.com and add emails like this one?


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